SEGONDBOOK 


HEW    YORK 

AUYNARkMERRlLL,*:  CO, 
43,45  &  47  £M.:   •••':•:- ST. 


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HUTCHISON  S    PHYSIOLOGICAL    SERIES 


LESSONS 


IN 


PHYSIOLOGY  AND  HYGIENE 

IN  Two  BOOKS 


SECOND  BOOK 

FOR  ADVANCED  GRADES 
JOHJM  S.  PRELL 
Civil  &  Mechanical  Engineer. 

SAN  FRANCISCO,  GAL. 

NEW    YORK 

MAYNARD,    MERRILL,    &   CO. 

43,  45,  and  47  East  Tenth  Street 
1895 


COPYRIGHT  1895 

MAYNARD,   MERRILL,   &  Co. 


GIFT 


H8Q 
Educ 


TO    MY    WIFE, 


WHOSE      SYMPATHY      HAS,       FOB      MOKE      THAN       TWENTY       YEARS,       LIGHTENED      THE      CAfiES 

INCIDENT      TO 

AN     ACTIVE     PROFESSIONAL     LIFE, 

THIS     HUMBLE      VOLUME 

IS      AFFECTIONATELY      INSCRIBED. 


196 


PKEFACE 


THIS  work  is  designed  to  present  the  leading  facts  and 
principles  of  human  physiology  and  hygiene  in  clear  and 
concise  language,  so  that  pupils  in  schools  and  colleges,  and 
readers  not  familiar  with  the  subjects,  may  readily  compre- 
hend them.  Anatomy,  or  a  description  of  the  structure  of 
an  organ,  is  of  course  necessary  to  the  understanding  of  its 
physiology,  or  its  uses.  Enough  of  the  former  study  has, 
therefore,  been  introduced  to  enable  the  pupil  to  enter  intel- 
ligently upon  the  latter. 

Familiar  language,  as  far  as  practicable,  has  been  em 
ployed,  rather  than  that  of  a  technical  character.  With  a 
view,  however,  to  supply  what  might  seem  to  some  a  defi- 
ciency in  this  regard,  a  Pronouncing  Glossary  has  been 
added,  which  will  enable  the  inquirer  to  understand  the 
meaning  of  many  scientific  terms  not  in  common  use. 

In  the  preparation  of  the  work  the  writer  has  carefully 
examined  all  the  best  material  at  his  command,  and  freely 
used  it  ;  the  special  object  being  to  have  it  abreast  of  the 
present  knowledge  on  the  subjects  treated,  as  far  as  that  is 
possible  in  a  work  so  elementary  as  this.  The  discussion  of 
disputed  points  has  been  avoided,  it  being  manifestly  inap- 
propriate in  a  work  of  this  kind. 

The  aim  of  a  text-book  on  physiology  for  schools  and  col- 
leges should  be  to  present  in  the  simplest  and  clearest  pos- 
sible manner  the  well-established  facts  of  the  subject  to  be 
taught,  so  that  the  students  may  obtain  an  intelligent  idea  of 


Vi  PREFACE 

the  workings  and  uses  of  the  human  body.  It  should  be 
scientific  enough  to  be  clear  and  logical,  and  to  appeal  to 
reason,  not  a  mere  compilation  of  facts  to  be  learned  by  rote. 
To  make  it  preparatory  to  a  higher  course  in  physiology 
would  be  manifestly  a  mistake,  for  it  would  necessitate  a 
much  more  scientific  plan  of  arrangement,  and  the  introduc- 
tion of  an  amount  of  material  which  would  be  confusing. 
The  teaching  of  anatomy  and  physiology  in  schools  should 
be  considered  chiefly  as  an  aid  in  teaching  hygiene,  so  that 
the  student  may  learn  how  to  live  a  most  healthful  life. 

The  present  edition  has  been  carefully  revised  and  cor- 
rected, and  considerable  new  material  has  been  added  on  the 
influence  of  alcohol  and  narcotics  on  health.  There  has  also 
been  added  an  appendix,  containing  some  simple  experi- 
ments and  anatomical  demonstrations,  which  are  suggested 
as  an  aid  to  the  teacher  in  presenting  the  subject  to  the  class. 
All  the  experiments,  as  weil  as  the  anatomical  demonstra- 
tions, are  simple,  and  the  teacher  will  have  no  difficulty  in 
reproducing  them.  Should  there  be  failures  at  first,  a  little 
patience  and  a  few  trials  will  soon  be  followed  by  success. 
All  complex  dissections  on  recently  killed  animals,  as  well 
as  all  vivisections  upon  frogs,  etc.,  have  purposely  been 
omitted,  not  only  because  they  are  unnecessary  in  teaching 
the  rudiments  of  anatomy  and  physiology,  but  also  because 
they  would  create  disgust  and  abhorrence  in  the  majority  of 
pupils. 

The  writer  desires  to  acknowledge  his  indebtedness  to  R. 
M.  Wyckoff,  M.D.,  for  valuable  aid  in  the  preparation  of  the 
manuscript  for  the  press;  and  to  R.  Cresson  Stiles,  M.D.,  a 
skillful  microscopisb  and  physician,  for  the  chapter  "On  the 
Use  of  the  Microscope  in  the  Study  of  Physiology." 

NEW  YORK,  May,  1894. 


CONTENTS, 


CHAPTER  X. 

9iam 

THE  FRAMEWORK  OF  THE  BODY. 

The  Bones — Their  form  and  composition — The  Properties  of  Bone — 
The  Skeleton — The  Joints — The  Spinal  Column — The  Growth  of 
Bone — The  Repair  of  Bone — Changes  &».  thz  Skeleton — Erect 
Position 15 

CHAPTER  IL 

THE    MUSCLES. 

The  Muscles— Flexion  and  Extension— The  Tendons— Contraction— 
Physical  Strength — Necessity  for  Exercise — Its  Effects — Forms  of 
Exercise  —  Walking — Riding —  Gymnastics —  Open-air  Exercise — 
Excessive  Exercise — Sleep — Recreation 31 

CHAPTER  m. 

THE  INTEGUMENT,   OR    SKIN. 

The  Integument — Its  Structure — The  Nails  and  Hair — The  Complex- 
ion— The  Sebaceous  Glands— The  Perspiratory  Glands — Perspi- 
ration and  its  uses — Importance  of  Bathing — Different  kinds  of 
Baths — Manner  of  Bathing— The  Benefits  of  the  Sun — Impor- 
tance of  Warm  Clothing — Poisonous  Cosmetics 48 

CHAPTER  IV. 

THE  CHEMISTRY  OF  FOOD. 

The  Source  of  Food—Inorganic  Substances — Water — Salt — Lime— 
Iron — Organic  Substances— Albumen,  Fibrin,  and  Caseine — The 
Fats  or  Oils—The  Sugars,  Starch,  and  Gum — Stimulating  Sub- 
stances— Necessity  of  a  Regulated  Diet. 65 


CONTENTS. 


CHAPTER  V. 

PAQB 
POOD  AND  DRINK. 

Necessity  for  Food —  Waste  and  Repair — Hunger  and  Thirst — Amount 
of  Food — Renovation  of  the  Body — Mixed  Diet — Milk — Eggs — 
Meat — Cooking — Vegetable  Food— Bread — The  Potato — Fruits — 
Purity  of  Water — Action  of  Water  upon  Lead— Coffee,  Tea,  and 
Chocolate—Effects  of  Alcohol 81 

CHAPTER  VL 

DIGESTION. 

The  Principal  Processes  of  Nutrition — The  General  Plan  of  Diges- 
tion— Mastication — The  Teeth — Preservation  of  the  Teeth — Insali- 
vation — The  Stomach  and  the  Gastric  Juice — The  Movements  of 
the  Stomach— Gastric  Digestion — The  Intestines — The  Bile  and 
Pancreatic  Juice — Intestinal  Digestion — Absorption  by  means  of 
Blood-vessels  and  Lacteals — The  Lymphatic  or  Absorbent  System 
— The  Lymph — Conditions  which  affect  Digestion — The  Quality, 
Quantity,  and  Temperature  of  the  Food — The  Influence  of  Exer- 
cise and  Sleep— The  Kidneys— The  Spleen— Effect  of  Alcohol 
upon  Digestion,  the  Liver,  and  Kidneys 104 

CHAPTER  VH. 

THE    CIRCULATION. 

The  Blood — Its  Plasma  and  Corpuscles— Coagulation  of  the  Blood — 
The  Uses  of  the  Blood—  Transfusion—  C7>/wge  of  Color— The 
Organs  of  the  Circulation — The  Heart,  Art&ries,  and  Veins — The 
Cavities  and  Valves  of  the  Heart — Its  Vital  Energy — Passage  of 
the  Blood  through  the  Heart — The  Frequency  and  Activity  of  its 
Movements — The  Pulse — The  Sphygmograph — The  Capillary 
Blood-vessels — The  Rate  of  the  Circulation — Assimilation — Inju- 
ries to  the  Blood-vessels — Effects  of  Alcohol  upon  the  Heart — As  a 
Fat-Producer 129 

CHAPTER  VHL 

RESPIRATION. 

The  Objects  of  Respiration — The  Lungs— The  Air-Passages — The 
Movements  of  Respiration — Expiration  and  Inspiration — The 
Frequency  of  Respiration — Capacity  of  the  Lungs — The  Air  we 
Breathe — Changes  in  the  Air  from  Respiration — Changes  in  the 


CONTENTS.  7 

PAGE 

Blood — Interchange  of  Gases  in  the  Lungs— Comparison  between 
Arterial  and  Venous  Blood — Respiratory  Labor — Impurities  of 
the  Air — Dust — Carbonic  Acid — Effects  of  Impure  Air — Nature's 
Provision  for  Purifying  the  Air —  Ventilation — Animal  Heat. . . .  154 

CHAPTER  IX. 

THE   NERVOUS   SYSTEM. 

Animal  and  Vegetative  Inunctions — Sensation,  Motion,  and  Volition— 
The  Structure  of  the  Nervous  System — The  White  and  Gray  Sub' 
stances— The  Brain — Its  Convolutions — The  Cerebellum — The  Spi- 
nal Cord  and  its  System  of  Nerves — The  Anterior  and  Posterior 
Roots —  The  Sympathetic  System  of  Nerves —  The  Properties  of  Nerv- 
ous Tissue — Excitability  of  Nervous  Tissues — The  Functions  of  the 
Spinal  Nerves  and  Cord — The  Direction  of  the  Fibres  of  the  Cord — 
Reflex  Activity  and  its  Uses— The  Functions  of  the  Medulla  Oblon- 
gata  and  the  Cranial  Ganglia— The  Reflex  Action  of  the  Brain 
—Effects  of  Alcohol,  Tobacco,  Snuff,  Narcotics,  Opium,  Chloral, 
Hasheesh,  Chloroform 181 

CHAPTER  X. 

THE  SPECIAL  SENSES.  * 

The  Production  of  Sensations—  Variety  of  Sensations— General  Sensi- 
bility— Pain  and  its  Function — Special  Sensation,  Touch,  Taste, 
Smell,  Sight,  and  Hearing — The  Hand,  the  Organ  of  Touch — Tht 
Sense  of  Touch — Delicacy  of  Touch — Sensation  of  Temperature 
and  Weight— The  Tongue  the  Organ  of  Taste— The  Nerves  of 
Taste — Tlie  Sense  of  Taste,  and  its  Relations  with  the  other  Senses 
— The  Influence  of  Education  on  the  Taste — The  Nasal  Cavities, 
or  the  Organs  of  SmeU—The  Olfactory  Nerve— The  Uses  of  the 
Sense  of  Smell— The  Sense  of  Sight— Light— The  Optic  Nerve— 
The  EyebaU  and  its  Coverings— The  Function  of  the  Iris— The 
Sclerotic,  Choroid,  and  Retina — The  Tears  and  their  Function — 
The  Movements  of  the  EyebaU— The  Function  of  Accommodation 
— The  Sense  of  Hearing  and  Sound — The  Ear,  or  the  Organ  of 
Hearing— The  External,  Middle,  and  Internal  Ear 220 

CHAPTER  XL 

THE  VOICE. 

Voice  and  Speech— The  Larynx,  or  the  Organ  of  the  Voice— The 
Vocal  Cords — The  Laryngoscope— The  Production  of  the  Voice — 
The  Use  of  the  Tongue — The  Different  Varieties  of  Voice — The 
Change  of  Voice — Its  Compass — Purity  of  Tone—  Ventriloquy... .  271 


8  CONTENTS. 

CHAPTER  XIL 

THE  USE  OF  THE  MICROSCOPE  IN  THE  STUDY  OF  PHYSIOLOGY. 

The  Law  of  Tissues — Necessity  of  the  Microscope — Different  kinds  of 
Microscopes — Additional  Apparatus — Preliminary  Studies — The 
Study  of  Human  Tissues — Tissues  of  the  Inferior  Animals — In- 
centives to  Study 283 

APPENDIX. 

POISONS  AND  THEIR  ANTIDOTES 290 

DROWNING 293 

CARE  OF  THE  SICK-ROOM 293 

DISINFECTION 295 

EMERGENCIES 297 

HOME  AND  HEALTH 300 

ON  GOING  INTG  THE  COUNTRY 302 

EXPERIMENTS 303 

EXERCISES  FOR  HOME  GYMNASTICS. 309 

GLOSSARY , 312 


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LIST  OF  ILLUSTRATIONS. 

no. 

FRONTISPIECE. 

VISCERA  IN  POSITION.  PAOT. 

1.  Section  of  bone,        .  17 

2.  The  skeleton,        .     -  ,-- 18 

3.  Structure  of  bone,  magnified,  ,        .         .        .  19 

4.  Ribs  in  natural  and  healthy  state,  »         .         ,         .       20 

5.  Ribs  showing  effects  of  tight  lacing,   ....  20 

6.  Cells  of  cartilage, 21 

7.  Elbow-joint,     .         .         .        .        .         .  .      .         .  22 

8.  Spinal  column,  .  ; 23 

9.  The  muscles,     .         .....         .         .  30 

10.  Muscular  tissue,  magnified,   .         .        .        .         .         .       31 

1 1.  Biceps  muscle  of  the  arm,  .....  32 

12.  Muscles  and  tendons  of  the  hand,  ....       33 

13.  Lower  portion  of  the  leg,  .         .         ...  34 

14.  Yiew  of  knee-joint,       •  *     •         •         •        •        •         .35 

15.  Appliance  for  strengthening  the  muscles,    ...  43 

16.  Appliance  for  strengthening  the  muscles,        ...       43 

17.  Root  and  transverse  section  of  hair,  magnified,    .         .  50 

18.  Section  of  skin,    .         .         .         .         .         ...       52 

19.  Granules  of  potato  starch,          .         .         .         .         .  76 

20.  Section  of  the  trunk, .105 

21.  Section  of  a  tooth,    .       ~+        .         .        .  '.     .        .         106 

22.  Section  of  the  jaws,      . 107 

23.  Section  of  the  jaws — right  side,          ..        .         «         .         108 

24.  Structure  of  a  salivary  gland,         •   •'    •         .         .         .110 

25.  Head  of  a  horse,  showing  salivary  gland,  etc.,     .         .         Ill 

26.  Section  of  chest  and  abdomen,       .         .         .         .         .114 

27.  Alimentary  canal,      .         .         .         .         .         .         .         115 

28.  The  lacteals,          .         .         .        .        .        .        .        .120 

29.  The  kidneys  and  bladder,  .         .         .         .         .         124 

30.  Blood  corpuscles,  highly  magnified,        .         .         .         .130 

31.  Blood  corpuscles  of  man  and  lower  animals,  magnified,         131 

32.  Circulation  of  the  blood,      )  Q        Ue  ^        ^     137 

33.  External  view  of  the  heart,  I 


10  LIST   OF   ILLUSTRATIONS. 

FIO.  PAOB 

34.  Section  of  the  heart,          .        .      -.        •.        . .;     .         138 

35.  Left  section  of  the  heart,     ) 

36.  Right  section  of  the  heart,  /  °PP°£     '    * 

37.  Form  of  the  pulse,    .         .        ...        .        .         144 

38.  Valves  of  the  veins,      .         .        .       ...*•»        .         .145 

39.  Web  of  frog's  foot,  magnified,    .         .        .        .  •       .         146 

40.  Circulation  in  a  frog's  foot,  .         .         .         .         .146 

41.  Organs  of  the  chest,         -.        ...        ."        .         .         155 

42.  Larynx,  trachea,  and  bronchial  tubes,    „         .         .         .156 

43.  Diagram  of  the  structure  of  the  air-cells,     .         .         .         156 

44.  Section  of  the  lungs,     .         .        .        ,         .        .         .157 

45.  Section  of  mouth  and  throat,      .         .         .        ;         .         158 

46.  Ciliated  cells,       .         .         .         .         .         .         .         .159 

47.  Ventilation  by  window,     .         .         .  .         .         175 

48.  Cerebro-spinal  system, 184 

49.  Upper  surface  of  the  cerebrum,  .         .         .         .         .         185 

50.  Vertical  section  of  the  brain, 186 

51.  Base  of  the  brain, 187 

52.  Brain  and  spinal  cord,  .         .         .         .         .         .         .188 

53.  Section  of  spinal  cord, 189 

54.  Sense  of  touch, 229 

55.  Section  of  nasal  cavity,  .  t 237 

56.  Front  view  of  the  eye,  ......     243 

57.  Vertical  section  of  the  eye,  magnified,         .         .         .         246 

58.  Front  section  of  eyeball,         ......     249 

59.  Diagram  of  blind  point  of  the  eye,      ....         250 

60.  The  retinal  image, 253 

61.  The  different  shapes  of  the  globe  of  the  eye,        .         .      '255 

62.  The  function  of  accommodation,     .....     257 

63.  The  ear  and  its  different  parts, 260 

64.  Showing  the  internal  mechanism  of  the  ear,  magnified,   .     262 

65.  Section  of  the  right  ear, 264 

66.  Section  of  the  larynx  and  trachea,  ....     274 

67.  A  view  of  the  vocal  cords  by  means  of  the  laryngoscope,      275 

68.  The  different  positions  of  the  vocal  cords,       .         .         .276 

69.  Double  convex  and  plano-convex  lenses,     .         .         .         283 

70.  Simple  microscope,        .         .         .         .         .         .         .284 

71.  Compound  microscope, 285 


INTRODUCTION. 


E  Human  Body  is  the  abode  of  an  immortal  spirit,  and  is  the 
most  complete  and  perfect  specimen  of  the  Creator's  handiwork. 
To  examine  its  structure,  to  ascertain  the  uses  and  modes  of  action 
of  its  various  parts,  how  to  protect  it  from  injury,  and  maintain  it  in 
a  healthy  condition,  is  the  design  of  this  work. 

The  departments  of  knowledge  which  are  concerned  in  these 
investigations,  are  the  science  of  Human  Physiology  and  the  art 
of  Hygiene. 

PHYSIOLOGY  treats  of  the  vital  actions  and  uses  of  the  various 
parts  of  living  bodies,  whether  vegetable  or  animal.  Each  living 
thing,  therefore,  has  a  Physiology.  "We  have  a  Vegetable  Physi- 
ology, which  relates  to  plants ;  and  an  Animal  Physiology,  relating 
to  the  animal  kingdom.  The  latter  is  also  divided  into  Comparative 
Physiology,  which  treats  of  the  inferior  races  of  animals,  and 
Human  Physiology,  which  teaches  the  uses  of  the  various  parts  of 
the  human  body. 

HYGIENE,  or  the  art  of  preserving  health,  is  the  practical  use  of 
Physiology.  It  teaches  us  how  to  cultivate  our  bodily  and  mental 
powers,  so  as  to  increase  our  strength,  and  to  fit  us  for  a  higher 
enjoyment  of  life.  It  also  shows  us  how  to  prevent  some  of  the 
accidents  which  may  befall  the  body,  and  to  avoid  disease.  It  is 


12  INTRODUCTION. 

proper  that  we  should  understand  the  construction  and  power  of  our 
bodies ;  but  it  is  our  duty,  as  rational  beings,  to  know  the  laws 
by  which  health  and  strength  may  be  maintained  and  disease 
warded  of£ 

There  are  various  means  by  which  we  gain  important  information 
respecting  the  Physiology  of  man.  Plants  aid  us  in  understanding 
the  minute  structure  of  the  human  body,  its  circulation,  and 
absorption.  From  inferior  animals  we  learn  much  in  respect  to  the 
workings  of  the  different  organs,  as  we  call  those  parts  of  the  system 
which  have  a  particular  duty  to  perform.  In  one  of  them,  as  in  the 
foot  of  the  frog,  we  can  study  the  circulation  of  the  blood;  in  an 
other,  we  can  study  the  action  of  the  brain. 

By  vivisection,  or  the  laying  bare  of  some  organ  of  a  living  animal, 
we  are  able  to  investigate  certain  vital  processes  which  are  too  deeply 
hidden  in  the  human  body  to  be  studied  directly.  This  is  not  necessa- 
rily a  cruel  procedure,  as  we  can,  by  the  use  of  anaesthetics,  so  blunt 
the  sensibility  of  the  animal  under  operation,  that  he  need  not  suffer 
while  the  experiment  is  being  performed.  There  are  other  means 
by  which  we  gather  our  information.  There  are  occasionally  men, 
who,  from  some  accident,  present  certain  parts,  naturally  out  of 
view,  in  exposed  positions.  In  these  cases,  our  knowledge  is  of 
much  greater  value  than  when  obtained  from  creatures  lower  in  the 
scale  of  being  than  man. 

"We  are  greatly  aided,  also,  by  the  use  of  various  instruments  of 
modern  invention.  Chief  among  these  is  the  microscope,  which  is, 
as  we  shall  learn  hereafter,  an  arrangement  and  combination  of 
lenses  in  such  a  way  as  greatly  to  magnify  the  objects  we  wish  to 
examine. 

We  have  much  to  say  of  Life,  or  vital  activity,  in  the  course  of 
our  study  of  Physiology ;  but  the  most  that  we  know  of  it  is  seen 
in  its  results.  What  Life  is,  or  where  its  precise  position  is,  we  are 
not  able  to  determine.  We  discover  one  thing,  however,  that  all 


INTRODUCTION.  13 

the  parts  of  the  body  are  united  together  with  wonderful  sympathy, 
so  that  one  part  cannot  be  injured  and  other  parts  not  suffer  damage. 
It  is  further  evident  that  all  organs  are  not  equally  important  in 
carrying  on  the  work  of  Life;  for  some  may  temporarily  suspend 
their  action,  without  serious  results  to  the  system,  while  others  must 
never  cease  from  acting.  Yet  there  is  nothing  superfluous  or  with- 
out aim  in  our  frames,  and  no  part  or  organ  can  suffer  harm  without 
actual  loss  to  the  general  bodily  health.  On  this  point  Science  and 
Holy  Writ  strictly  agroe. 


PHYSIOLOGY  AND   HYGIENE, 


THE  FRAMEWOKK  OF  THE  BODY. 

The  Bones — Their  Form  and  Composition — The  Properties  of  Bone — The 
Skeleton— The  Joints— The  Spinal  Column— The  Growth  of  Bone— The 
Repair  of  Bone — Changes  in  the  Skeleton — Erect  Posture. 

1.  The  Bones. — The  framework  which  sustains  the  human  body 
is   composed  of  the  Bones.      The  superstructure  consists  of  the 
various  organs  on  which  the  processes  of  life  depend.     These  or- 
gans are  soft  and  delicately  formed,  and,  if  unprotected,  would,  in 
most  cases,  rapidly  be  destroyed  when  subjected  to  violence,  how- 
ever slight.     The  bones,  having  great  strength  and  power  of  resist- 
ance, afford  the  protection  required.     (Read  Note  i. ) 

2.  The  more  delicate  the  organ,  the  more  completely  does  Nature 
shield  it.     For  example :  the  brain,  which  is  soft  in  structure,  is 

1.  Self-Knowledge. — "  It  has  been  said  with  truth  that  the  human  mind, 
which  can  survey  the  heavens  and  calculate  the  motion  and  density  of  the 
stars,  finds  itself  confounded  when,  returning  from  these  distant  journeyings, 
it  enters  its  own  dwelling-place — the  body.  Man's  own  organization  is  still 
among  those  mysteries  of  nature  which  he  is  least  able  to  penetrate,  in  spite 
of  his  incessant  efforts  to  lift  the  veil  which  hides  it.  In  all  ages  he  has  sought 
to  know  himself.  In  all  times  he  has  studied  the  relations  between  his  own 
existence  and  that  of  the  world,  and  those  universal  influences  which,  though 
evident  to  him,  are  nearly  all  inexplicable  in  their  action  upon  living  beings." 
— Le  Pileur  on  the  Human  Body. 


1.  The  framework  of  the  body?  The  superstructure?     Softness  and  delicacy  of  the 
organs?    How  protected ?  *- 

2.  The  more  delicate  the  organ?  Example  in  relation  to  th§  brain?     The  eye?    The 
lungs  ?    The  services  performed  by  t 


16  THE  FRAMEWORK  OP  THE  BODY. 

enclosed  on  all  sides  by  a  spherical  box  of  bone ;  the  eye,  though  it 
must  be  near  the  surface  of  the  body  to  command  an  extensive 
view,  is  sheltered  from  injury  within  a  deep  recess  of  bone ;  the 
lungs,  requiring  freedom  of  motion  as  well  as  protection,  are  sur- 
rounded by  a  large  "  chest "  of  bone  and  muscle.  The  bones  serve 
other  useful  purposes.  They  give  permanence  of  form  to  the  body, 
by  holding  the  softer  parts  in  their  proper  places.  They  assist  in 
movement,  by  affording  points  of  attachment  to  those  organs  which 
have  power  of  motion — the  muscles. 

3.  The  Form  and  Composition  of  the  Bones. — The  shape 
and  size  of  the  bones  vary  greatly  in  different  parts  of  the  body, 
but  generally  they  are  arranged  in  pairs,  one  for  each  side  of  the 
body.     They  are  composed  of  both  mineral  and  animal  substances, 
united  in  the  proportion  of  two  parts  of  the  former  to  one  of  the 
latter;  and  we  may  separate  each  of  these  substances  from  the 
other  for  examination.     First,  if  we  expose  a  bone  to  the  action  of 
fire,  the  animal  substance  is  driven  off,  or  "  burned  out."     "We  now 
find  that,  though  the  shape  of  the  bone  is  perfectly  retained,  what 
is  Left  is  no  longer  tough,  and  does  not  sustain  weight  as  before. 
Again,   we    may  remove  the  mineral  portion,   which  is  a   form 
of  lime,  by  placing  a  bone  into  a  dilute  acid.      The    lime  will 
be  dissolved  out,  and  the  shape  of  the  bone  remain  as  before; 
but  now  its  firmness  has  disappeared,  and  it  may  be  bent  without 

breaking.     (See  Appendix,  page  303.) 

4.  If,  for  any  reason,  either  of  these  ingredients  is  disproportion- 
ate in  the  bone  during  life,  the  body  is  in  danger.     The  mineral 
substance  is  useful  in  giving  rigidity  of  form,  while  the  animal  sub- 
stance insures  toughness  and  elasticity,  so  that  by  their  union,  WP- 
are  able  to  withstand  greater  shocks  and  heavier  falls  than  would 
be  possible  with  either  alone.     In  youth,  the  period  of  greatest 
activity,  the  animal  portion  is  in  excess;  abooe  then  does  not  break 
so  readily,  but,   when  broken,    unites  with  great   rapidity  and 
strength.     On  the  other  hand,  the  bones  of  old  persons  are  more 
easily  broken,  and  in  some  cases  fail  to  unite.     The  mineral  matter 

3.  Their  shape  and  size?    Of  what  composed  ?    Possibility  of  being  separated?   Effect 
of  fire?    Of  dilute  acid? 

4.  Effect  of  deficiency  of  ingredient  ?    Usefulness  of  the  lime  ?   Of  the  animal  substance  f 
Effect  of  their  union?    Condition,  in  youth  ?    Old  age? 


THE  FRAMEWORK  OF  THE  BODY. 


17 


being  then  in  excess,  indicates  that  the  period  of  active  exertion  is 
drawing  to  a  close.     (Read  Note  2). 

5.  The  Structure  of  the  Bones. — If  we  examine  one  of  the 
long  bones,  which  has  been  sawed  through  lengthwise,  we  observe 


Fio.  1.— SECTION  OF  BONE.— A.  Longitudinal.    B.  Trans- 
verse Section  of  Bone. 

(See  Appendix,  page  304.) 


that  it  is  admirably  fashioned  for  affording  lightness  as  well  as 
strength  (Fig.  1).  Its  exterior  is  hard  and  resisting,  but  it  is 
porous  at  the  broad  extremities,  while  through  the  central  portion 


2.  Some  Properties  of  Bone. — "The  power  of  bone  to  resist  decay  is 
remarkable.  Fossil  bones  deposited  in  the  ground  long  before  the  appearance 
of  man  upon  the  earth  have  been  found  by  Cuvier,  exhibiting  a  considerable 
portion  of  "cartilage.  The  jaw  of  the  Cambridge  Mastodon  contained  over 
forty  per  cent,  of  animal  matter — enough  to  make  a  good  glue — and  others 
about  the  same.  From  this  we  see  that  a  nutritious  soup  might  be  made  from 
the  bones  of  animals  that  lived  before  the  creation  of  man.  The  teeth  resemble 
bo'ie  in  their  structure,  but  resist  decay  longer  ;  they  are  brought  up  by  deep- 
sea  dredging,  when  all  other  parts  of  the  animal  have  wasted  away.  The 
bones  differ  at  different  ages,  and  under  different  social  conditions.  In  the 
disease  called  'rickets,'  quite  common  among  the  ill-fed  children  of  the  poor 
in  Europe,  but  somewhat  rare  in  America,  there  is  an  inadequate  deposit  of 
the  mineral  substance,  rendering  the  bones  so  flexible  that  they  may  be  bent 
almost  like  wax.  In  females  and  weak  men  the  bones  are  light  and  thin, 
while  in  a  powerful  frame  they  are  dense  and  heavy.  Exercise  is  as  necessary 
to  the  strength  of  bone  as  to  the  strength  of  muscle  ;  if  a  limb  be  disused, 
from  paralysis  or  long  sickness,  the  bones  lose  in  weight  and  strength  as  well 
as  the  soft  parts.  Bone  is  said  to  be  twice  as  strong  as  oak,  and,  to  crush  a 
cubic  inch  of  it,  a  pressure  equal  to  5,000  pounds  is  requisite." 


5.  In  what  respect  admirably  fashioned?    Its  formation? 
The  inference  ?    "  Line  of  beauty  ? " 


Microscopic  examination? 


18 


THE   FRAMEWORK  OF   THE  BODY. 


Fio.  2.— THE  SKELETON 


THE  FRAMEWORK  OF  THE  BODY. 


19 


there  is  a  cavity  or  canal  which  contains  an 
oily  substance,  called  marrow.  If  a  thin 
section  of  bone  be  examined  under  the  mi- 
croscope, we  discover  that  it  is  pierced  by 
numerous  fine  tubes  (Fig.  3),  about  which 
layers  of  bone-substance  are  arranged.  So 
that,  although  a  bone  be  as  hard  as  stone 
externally,  it  is  by  no  means  as  heavy,  by 
reason  of  its  light  interior  texture.  An- 
other element  of  power  is  found  in  the 
curved  outline  of  the  bones.  The  curved 
line  is  said  to  be  "  the  line  of  beauty,"  as  it 
certainly  is  the  line  of  strength,  and  is  uni- 


Fio.  3.— STRUCTURE  OF  BONK 
ENLARGED. 


formly  present  in  the  bones  whose  position  exposes  them  to  accident. 
S  6.  The  Skeleton.  —  The  number  of  bones  in  the  human  body 
^^--fixceeds  two  hundred,  and  when  joined  together  in  their  proper 
places,  they  form  what  is  termed  the  Skeleton  (Fig.  2).  It  embraces 
three  important  cavities.  The  first  of  these,  surmounting  the  frame, 
is  a  box  of  bone,  called  the  skull;  below  this,  is  a  bony  case,  or 
"chest;"  and  lower  down  is  a  bony  basin,  called  the  pelvis.  The 
two  latter  compose  the  trunk.  The  trunk  and  skull  are  maintained 
in  their  proper  relations  by  the  "  spinal  column."  Branching  from 
the  trunk  are  two  sets  of  limbs  :  the  arms,  which  are  attached  to 
the  chest  by  means  of  the  "collar-bone"  and  "shoulder-blade;'* 
and  the  legs,  directly  joined  to  the  lower  part  of  the  trunk. 
(Read  Not 


3.  Two  Forms  of  Skeleton  among  Animals.  —  "The  solid  basis  on 
which  all  the  soft  organs  of  the  body  rest  is  the  skeleton.  In  the  human  body 
the  skeleton  is  composed  of  a  number  of  bones,  each  of  which  has  a  distinct 
name.  In  the  animal  kingdom  there  are  two  distinct  forms  of  skeletons  ;  the 
one  which  is  found  chiefly  in  the  lower  animals  is  outside,  and  covers  the  soft 
parts,  and  is  called  an  exo-skeleton.  Examples  of  this  kind  of  skeleton  are 
seen  in  crabs,  lobsters,  insects,  and  the  shells  of  mollusca,  as  oysters,  mussels, 
and  whelks.  The  shells  of  these  animals  are  mostly  composed  of  carbonate  of 
lime.  Fishes  possess  an  internal  skeleton  ;  and  all  the  classes  of  animals  above 
them,  as  reptiles,  birds,  and  mammals,  possess  internal  or  endo-skeletons."—  « 
Lankester's  Manual  of  Health. 


6.  Number  of  bones?    Skeleton?    The  skull?    Chest?    The  trunk?    The  trunk  and  skull, 
bow  maintained  ?    What  of  the  arms  ?    Legs  f 


20  THE  FRAMEWORK  OF  THE  BODY. 

7.  The  cavities,  three  of  which  we  have  mentioned,  are  designed 
for  the  lodgment  and  protection  of  the  more  delicate  and  perishable 
parts  of  the  system.  Thus,  the  skull,  together  with  the  bones  of 
the  face,  shelters  the  brain  and  the  organs  of  four  senses — sight, 
hearing,  smell,  and  taste.  The  chest  contains  the  heart,  lungs,  and 
great  blood-vessels,  while  the  lower  part  of  the  trunk  sustains  the 
liver,  stomach,  and  other  organs. 


Fio.  4.— RIBS  IN  A  NATURAL  AND  Pio.  5.— RIBS  SHOWING  THE  EFFECTB 

HEALTHY  STATE.  OF  TIGHT  LACING. 

8.  The  Joints. — The  point  of  union  of  two  or  more  bones 
forms  a  joint  or  articulation,  the  connection  being  made  in  vari- 
ous ways  according  to  the  kind  and  amount  of  motion  desired. 
The  movable  joints  are  connected  by  strong  fibrous  bands,  called 
ligaments.  These  ligaments  are  of  a  silvery  whiteness,  and  very 
unyielding ;  so  much  so,  that  when  sudden  violence  is  brought  to 
bear  in  the  vicinity  of  a  joint,  the  bone  to  which  a  ligament  is  at- 
tached may  be  broken,  while  the  ligament  itself  remains  uninjured. 
When  this  connecting  material  of  the  joints  is  strained  or  lacerated 
by  an  accident,  a  "  sprain  "  is  the  consequence.  An  injury  of  this 
sort  may  be,  and  frequently  is,  quite  as  serious  as  the  breaking  of  a 
bone.  (Read  Note  4. ) 

4.  How  Joints  may  be  Injured. — "All  the  joints  are  liable  to  disloca- 
tion— that  is,  being  '  put  out '  of  their  place.  Owing  to  the  shallowness  of 
the  cavity  at  the  shoulder,  this  Joint  is  frequently  dislocated  ;  and  this  some- 

7.  Design  of  the  cavities?    Give  the  examples. 

8.  Joint  or  articulation  ?    Movable  joints,  how  compacted  ?    The  ligaments  of  the  movable 
joints?   What  is  a  sprain?    Consequence  of  a  serious  sprain  ? 


THE  FRAMEWORK  OF  THE  BODY.  21 

9.  The  ligament,  then,  secures  firmness  to  the  joint ;  it  must  also 
have  flexibility  and  smoothness  of  motion.     This  is  accomplished 
by  a  beautiful  mechanism,  the  perfection  of  which  is  only  feebly 
imitated  by  the  most  ingenious  contrivance  of  man.     The  ends  of 
the  bones  are  covered  by  a  thin  layer  of  cartilage,  which,  being 
smooth  arid  elastic,  renders  all  the  movements  of  the  joint  very 
easy.     In  addition  to  this,  there  is  an  arrangement  introduced  fol 
"  lubricating  "  the  joint,  by  means  of  a  deli- 
cate sac  containing  fluid.    This  fluid  is  con- 
stantly supplied   in   small  quantities,  'but 

only  so  fast  as  it  is  used  up  in  exercise.  In 
appearance,  it  is  not  unlike  the  white  of 
an  egg,  and  hence  its  name  synovia,  or  egg- 
like. 

10.  Thus,  we  observe  that  two  very  dif- 
ferent substances  enter  into  the  composition 
of  a  joint.     The  ligament,  very  unyielding, 
affords  strength,  while  the  cartilage,  elastic 
and  moist,  gives  ease   and  smoothness  of 

motion.  The  amount  of  motion  provided  Fl°-  6--CELLS  OF  CARTILAGE. 
for  varies  greatly  in  different  joints.  In  some  there  is  none  at  all, 
as  in  the  skull,  where  one  bone  is  dove-tailed  into  another  by  what 
are  termed  sutures.  Others  have  a  hinge-like  motion,  such  as 
those  of  the  elbow,  wrist,  ankle,  and  knee ;  the  most  complete  of 
these  being  the  elbow-joint  (Fig.  7).  Belonging  to  another  class, 

times  happens  with  the  thigh,  but  not  so  often,  as  the  cup  in  which  the 
emur  moves  is  much  deeper.  Joints  which  have  been  dislocated  should  at 
once  be  '  set '  ;  but  now  that  you  have  seen  how  liable  you  are  to  accident, 
I  hope  you  will  be  careful  not  to  indulge  in  too  violent  or  rough  exercise,  by 
which  you  might  not  only  dislocate  the  joints,  and  so  in  time  weaken  them, 
but  might  also  break  the  bones,  and  perhaps  become  crippled  for  life.  Many 
children  have  the  habit  of  pulling  their  fingers  so  as  to  make  them  '  crack. 
This  is  exceedingly  wrong,  for  it  is  to  a  certain  extent  pulling  the  joints  out 
of  their  sockets,  and  this  may  so  loosen  the  parts  as  to  cause  permanent  in- 
jury."— Davidson's  "  Our  Bodies." 


9.  Office  of  the  ligament?     What  must  it  have?    How  accomplished ?    Describe  it. 
Synovia  ? 

10.  What  do  we  observe  as  regards  the  composition  of  a  joint  ?    The  ligament  and  carti- 
lage ?    What  varies  ?    Example  of  the  skull  ?    Other  examples  ?    The  ball-and-socket  joint  ? 


22 


THE    FRAMEWORK    OF   THE    BODY. 


the  ball-and-socket  joint,  is  that  at  the  shoulder,  possessing  a  free- 
dom of  motion  greater  than  any  other  in  the  body. 


Fig.  7.— ELBOW-JOINT.    A,  Bone  of  the  arm ;  B,  C,  Bones  of  the  fore-arm. 


11.  The  Spinal  Column. — The  spinal  column  is  often  spoken  of 
as  the  "  back-bone,"  as  if  it  were  a  single  bone,  while,  in  reality,  it 
is  composed  of  a  chain  of  twenty-six  small  bones,  called  vertebra. 
The  spinal  column  is  a  wonderful  piece  of  mechanism.     It  not  only 
connects  the  important  cavities  of  the  body,  as  has  already  been 
shown,  but  also,  itself  forms  a  canal,  which  contains  the  spinal 
cord.     The  joints   of  the   vertebras   are  remarkable  for  the  thick 
layers  of  cartilage  which  separate  the  adjacent  surfaces  of  bone. 
The  amount  of  motion  between  any  two  of  these  bones  is  not  great ; 
but  these  little  movements,  taken  together,  admit  of  very  consider- 
able flexibility,  in  several  directions,  without  endangering  the  sup- 
porting power  of  the  column. 

12.  The  abundant  supply  of  intervertebral  cartilage  has  another 
important  use,  namely,  it  adds  greatly  to  the  elasticity  of  the  frame. 
It  is  due,  in  part,  to  this  elastic  material,  and  in  part  to  the  fre- 
quent curves  of  the  spine,  that  the  brain  and  other  delicate  organs 


11.  What  is  the  spinal  column  ?    What  does  it  connect  and  form  ?    Joints  of  the  verte- 
brae ?    Amount  of  motion  ?    Result  ? 

12.  Elasticity  of  the  frame  ?    Protection  of  the  brain  from  shocks?    Tallness  of  persons} 
Effects  of  reclining  ? 


THE  FRAMEWORK:  OP  THE  BODY. 


23 


are  not  more  frequently  injured  by  the  shock  of  sudden  falls  or 
missteps.  During  the  day,  the  constant  pressure  upon  these  joints, 
while  the  body  is  erect,  diminishes  the  thickness  of  the  cartilages ; 
so  that  a  person  is  not  so  tall  in  the  evening  as  in  the  morning. 
The  effects  of  this  compression  pass  away 
when  the  body  is  in  a  reclining  posture. 
(Read  Note  5. ) 


5.  Some  Causes  of  Curvature  of  the 
Spine. — "Much  as  horse-riding  is  valued  on  ac- 
count of  the  healthful  character  of  its  exercise, 
yet  an  over-indulgence  by  young  ladies — owing 
to  the  oblique  position  in  which  the  female  form 
rests  in  the  side-saddle — will  cause  the  spine  to 
become  curved."  To  avoid  this,  it  is  important 
for  young  ladies  to  ride  occasionally  on  the  op- 
posite side  of  the  horse.  Another  frequent  cause 
of  curvature  of  the  spine  is  the  use  of  the  sewing- 
machine,  especially  among  needy  seamstresses, 
whose  hreacl  frequently  depends  on  the  almost  un- 
ceasing labor  of  their  hands  and  feet,  while  sitting 
in  a  constrained  position.  Soon  after  croquet  be- 
came a  favorite  amusement  among  the  fashionable 
young  ladies  of  England,  it  was  noticed  that  the 
bent  position  assumed  during  the  time  the  mallet 
is  used  caused  a  certain  deformity,  to  which  was 
given  the  name  of  the  "  croquet  curvature."  The 
use  of  high  heels  on  boots  and  shoes  of  children, 
by  throwing  the  weight  of  the  body  too  far  for- 
ward, on  the  front  of  the  foot,  and  destroying  the 
natural  poise  of  the  body,  acts  an  important  part 
in  causing  the  spine  to  become  crooked.  By  many 
this  crooked  position  is  considered  to  be  largely  a 
school-room  disease,  for  the  reason  that  children 
often  are  compelled  to  sit,  and  write  or  study,  in  a  Os  Coccygis. 
bent  posture ;  but  there  must  be  other  causes  for  it,  FIG.  8.— THE  SPINAL  COLUMN. 
since  it  has  been  found  that  it  is  almost  exclusively 

a  female  deformity.  Over  eighty-four  per  cent,  of  the  cases  is  stated  by  one 
writer  to  be  among  girls.  But  inasmuch  as  the  majority  of  these  cases  begin  dur- 
ing the  years  of  schooling— from  the  ages  of  six  to  fourteen— great  attention 
should  be  paid  to  the  position  of  the  body  during  school  hours,  and  ample  oppor- 
tunity should  be  offered,  by  a  regular  system  of  gymnastics,  to  counteract  all  the 
evil  influences  of  the  school-room  posture.  — Heather-£igg  on  Deformities  (in  pwrt}, 


Sacrum. 


24  THE  FRAMEWORK  OF  THE  BODY. 

13.  The  Growth  of  Bone. — Bone,  like  all  the  other  tissues  of 
the  body,  is  constantly  undergoing  change,  old  material  being  with- 
drawn, to  make  room  for  a  fresh  supply.     This  change  has  been 
shown   conclusively   by  experiments.     If  an  animal  be  fed  with 
madder — a  red  coloring  matter — for  a  day  or  two,  the  bones  soon 
become  tinged;  then,  if  the  madder  be  discontinued  for  a  few  days, 
the  original  color  returns.     If,  however,  this  material  be  alternately 
given  and  withheld,  at  short  intervals,  the  bone  will  be  marked  by 
a  succession  of  red  and  white  rings.     In  very  young  animals,  all 
the  bones  become  colored  in  a  single  day ;  in  older  ones,  a  longer 
time  is  required.     The  process  of  waste  and  repair,  therefore,  is 
constantly  taking  place -in  this  hard  substance,  and  with  astonishing 
rapidity. 

14.  The  Repair  of  Bone. — Nature's  provision  for  uniting  broken 
bones  is  very  complete.     At  first,  blood  is  poured  out  around  the 
ends  of  the  bone,  as  a  result  of  the  injury.     This  is  gradually  ab- 
sorbed, and  gives  place  to  a  watery  fluid,  which,  thickening  from 
day  to  day,  acquires,  at  the  end  of  about  two  weeks,  the  consistency  of 
jelly.  This  continues  to  harden,  by  the  deposit  of  new  bone-substance, 
until,  usually  at  the  end  of  five  or  six  weeks,  the  broken  bone  may 
be  said  to  be  united.     It  is,  however,  still  fragile,  and  must  be  used 
carefully  a  few  weeks  longer.     The  process  of  hardening  continues, 
but  months  must  pass  before  the  union  can  be  said  to  be  complete. 
(Read  Note  ^ 

6.  The  Management  of  a  Broken  Limb.— "Fractures  are  usually  met 
with  when  the  person  is  dressed.  Therefore,  unless  there  is  bleeding,  or  some- 
thing to  call  for  immediate  exposure  and  examination  of  the  damaged  part,  do 
not  be  in  a  hurry  to  remove  the  clothes.  If  the  arm  be  hurt,  extemporize  a 
sling  from  a  neck-handkerchief  or  some  other  article  of  dress,  and  support  the 
arm  from  elbow  to  wrist,  tying  the  ends  of  the  handkerchief  in  a  knot  over  the 
coat-collar  behind.  If  the  thigh  or  leg  be  in  pain,  fasten  the  injured  limb  to 
its  fellow  by  a  cravat  bandage  or  two,  and  take  care  that  they  lie  side  by  side, 
and  on  the  same  level ;  or  fasten  outside  the  clothes  some  temporary  support — 
a  piece  or  two  of  straight  stick,  with  a  bandage — and  then  remove  the  sufferer 
quietly  and  carefully  to  some  house  near  at  hand.  If  medical  aid  be  available, 


13.  Change  in  bone?     Example— animal  and  madder.     Rapidity  of  change  in  color? 
Waste  and  repair  ? 

14.  How  is  a  broken  bone  united?    What  becomes  of  the  blood  caused  by  the  injury  I 
What  takes  its  place  ?    H«w  long  does  it  usually  take  for  a  broken  bone  to  unite! 


THE  FRAMEWORK  OF  THE  BODY.  25 

15.  Changes  in  the  Skeleton. — Man  dops  not  reach  his  full 
height  until  he  is  about  twenty-five  years  oldc  and  even  after  that 
age,  the  bones  continue  to  increase  in  strength  and  hardness.     Be- 
fore that  age  they  are  comparatively  soft  and  flexible,  by  reason  of 
the  gelatin  they  contain.     This  is  especially  true  in  childhood ;  and 
it  is  fortunate  that  it  is  so,  since  that  condition  is  much  more  favor- 
able to  the  steady  and  rapid  growth  of  the  bones  than  if  they  con- 
tained more  of  the  lime,  as  is  the  case  in  old  age,  when  there  is  no 
occasion  for  change  in  the  size  or  shape  of  the  skeleton.     The  skull, 
however,  is  said  to  increase  slightly  in  size,  even  in  advanced  life, 
in  those  persons  in  whom  the  brain  is  continually  employed  in 
thought  or  study.     However,  this  very  flexibility  of  the  bones,  in 
early  life,  which  favors  their  steady  growth  and  prevents   their 
breaking  easily,  is  sometimes  the  source  of  serious  deformity.     A 
young  child  may  be  allowed  to  stand  and  walk  too  early,  and,  as  a 
consequence,  the  lower  limbs  become  permanently  bent  inward,  in 
the  distortion  called  "knock-knees,"  or  outward,  as  in  "bow-legs." 
For  the  same  reason,  a  bent  position  of  the  spinal  column,  permitted 
to  exist  habitually  in  childhood,  may  result  in  a  life-long  deformity. 

16.  The  Erect  Posture. — Youth  is,  in  a  great  measure,  the 
forming  as  well  as  the  growing  period  of  the  frame.     Bad  habits  of 
posture,  early  formed,  become  fixed  in  later  life,  and  their  results-^ 

send  for  it  without  any  delay ;  and  be  careful,  if  in  the  country,  and  so 
some  distance  from  the  doctor's  house,  to  forward  a  clear  statement  as  to  the 
apparent  nature  of  the  accident,  which  limb  is  hurt,  and  where  and  how  it 
happened.  Let  this  statement,  too,  be  in  writing,  if  possible.  It  may  well 
happen,  however,  that  skilled  assistance  cannot  be  had,  and  in  this  case  the 
patient  should  be  undressed  quietly  and  cautiously.  It  will  be  far  better  to  slit 
up  the  dress  on  the  arm  or  leg  with  a  pair  of  scissors  than  to  pull  it  off ;  but 
however  the  covering  of  the  injury  may  be  managed,  it  must  be  done  very 
slowly  and  gently,  and  the  limb  should  be  supported  so  as  to  prevent  jarring 
and  shaking  to  the  damaged  part.  It  must  be  carefully  kept,  too,  in  a  right 
direction,  for  otherwise  some  sharp  splinter  of  bone  may  penetrate  the  hitherto 
unwounded  skin."— First  Help  in  Accidents  and  Sickness. 


15.  When  does  a  man  get  his  growth  ?    What  changes  then  take  place  ?    What  difference 
In  the  bones  of  a  child  and  those  of  a  man  ?    What  exception  in  case  of  the  skull  ?    Benefit 
in  flexibility  of  bones?    Cause  of  knock-knees?    Bow-legs? 

16.  What  is  the  forming  period?    Effects  of  bad  habits  of  posture?    Directions  foi 
correct  posture? 


\     v 


26  THE  FRAMEWORK  OP  THE  BODY. 

as  seen  in  contracted  chests  and  round  shoulders — are  with  difficulty 
remedied.  Eight  habits,  on  the  other  hand,  tend  to  produce  an 
erectness  of  posture  which  is  favorable,  not  alone  to  strength  and 
health,  but  also  to  grace  and  ease.  The  following  directions  should 
be  learned  and  practiced :  hold  the  head  erect  with  the  chin  some- 
what near  the  neck  ;  expand  the  chest  in  front;  throw  the  shoul- 
ders back,  keeping  them  of  the  same  height  on  both  sides;  maintain 
the  natural  curves  of  the  spine,  as  shown  in  the  last  figure.  Man 
alone,  of  all  the  animals,  has  the  power  to  stand  and  move  in  the 
erect  postura 


THE   FRAMEWORK   OF   THE   BODY.  27 


QUESTIONS   FOR   TOPICAL   REVIEW. 

PAOB 

1.  What  useful  purposes  do  the  bones  serve?. 15,16 

2.  State  what  you  can  of  the  composition  of  the  bones 16 

3.  Of  the  usefulness  of  lime  in  the  bones 16 

4.  Of  the  usefulness  of  animal  substance  In  the  bones 16 

5.  State  what  you  can  of  the  structure  of  the  bones 17 

6.  Of  the  strength  belonging  to  the  bones 19 

7.  What  is  meant  by  the  human  skeleton? 19 

8.  Give  a  description  of  its  construction 19 

9.  What  is  meant  by  a  joint  in  the  human  frame? -..    20 

10.  State  what  you  can  of  the  movable  joints 20,  21 

11.  What  office  is  performed  by  the  ligaments  of  the  joints? 21 

12.  What  by  the  cartilage  at  the  joints? 21 

13.  What  movable  joints  are  there  ?.  21,22 

14.  Describe  the  construction  of  the  spinal  column. . .  22 

15.  What  properties  and  powers  does  the  spinal  column  possess  ? 22,  23 

16.  When  is  a  person  taller  than  at  other  times? 23 

17.  Give  the  reason  for  this 23 

18.  What  can  you  state  of  the  growth  of  bone? 24 

19.  Describe  the  process  by  which  a  broken  bone  is  repaired 24 

20.  When  does  man  reach  his  full  height  ?. 25 

21.  What  changes  in  the  bones  then  take  place  ?. 25 

22.  Name  an  exception  to  the  general  rule 25 

23.  State  the  advantage  and  disadvantage  in  the  flexibility  of  bones 25 

24.  What  directions  are  given  for  the  correct  position  2 ,»,,,.,,...... 26 


TABLE   OF  THE   SKELETON. 


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TABLE  OP  THE  SKELETON. 


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30 


THE   MUSCLES. 


Fia.  9.—  THE  MUSCLES. 


XL 

THE  MUSCLES. 

The  Muscles — Flexion  and  Extension — The  Tendons — Contraction — Physical 
Strength — Necessity  for  Exercise— Its  Effects — Forms  of  Exercise —  Walking 
— Riding —Gymnastics — Open-air  Exercise — Effects  of  Exercise— Excessive 
Exercise — Sleep — Recreation. 

1.  The  Muscles. — TnV  great  mass  of  the  body  external  to  the 
skeleton  is  composed  of  the  flesh,  or  Muscles,  which  largely  de- 
termines its  outline  and  weight.     The  muscles  are  the  organs  of 
motion.     Their  number  is  about  four  hundred,  and  to  each  of  them 
is  assigned  a  separate  and  distinct   office.     They  have  all  been 
studied,  one  by  one,  and  a  name  given  to  each,  by  the  anatomist. 
Each  is  attached  to  bones  which  it  is  designed  to  move.     A  few  are 
circular  in  form,  and  enclose  cavities,  the  size  of  which  they  dimin- 
ish by  contraction. 

2.  If  we  examine  a  piece  of  flesh,  we  observe  that  it  is  soft,  and 
of  a  deep  red  color.     Its  structure  appears  to  be  composed  of  layers 

and  bundles  of  small  fibres. 
Let  us  further  examine 
these  fibres  under  the  mi- 
croscope. We  discover 
that  these  in  turn  are 
made  up  of  still  finer 
fibres,  or  fibrillce,  as  shown 
in  Fig.  10.  The  fibres  are 
beautifully  marked  by  par- 
allel wavy  lines,  about  ten 
PIG.  IO.-MUSCULAB  TISSTJE.  thousand  to  an  inch,  which 

a,  ft,  Striped  muscular  fibres ;  c,  The  same  more  •         .->        r>->         . .  - 

highly  magnified.  give  the  fibre  its  name  of 


1.  What  are  the  muscles  ?    Their  number  ?    The  design  of  most  of  them  ?    Of  a  few  ? 

2.  The  structure  of  flesh  ?    Its  color,  etc.  ?  The  composition  of  the  fibres?  How  marked  ? 


32 


THE   MUSCLES. 


the  striped  muscular  fibre.     All  of  the  voluntary  muscles  present 

this  appearance. 
3.  Flexion   and  Extension. — The  muscles  are,  for  the  most 

part,  so  arranged  in  pairs,  or  corresponding  sets,  that  when  motion 
is  produced  in  one  direction  by  one  set,  there 
is,  opposite  to  it,  another  muscle,  or  group  of 
muscles,  which  brings  the  limb  back  to  its 
place.  "When  they  act  alternately,  a  to-and-fro 
movement  resuks.  When  a  joint  is  bent,  the 
motion  is  called  flexion  ;  and  when  it  is  made 
straight  again,  it  is  called  extension.  When 
both  sets  act  equally,  and  at  the  same  moment, 
no  motion  is  produced,  but  the  body  or  limb  is 
maintained  in  a  fixed  position :  this  occurs 
when  we  stand  erect.  The  muscles  which  pro- 
duce extension  are  more  powerful  than  those 
opposite  to  them. 

4.  The  muscles  are  also  distinguished  as  the 
voluntary  and  involuntary  muscles,  according 
as  they  are,  or  are  not,  under  the  control  of  the 
will.  The  heart  is  an  example  of  the  involun- 
tary variety.  We  cannot  change  its  action  in 
the  least  by  an  effort  of  the  will.  When  we 
sleep,  and  the  will  ceases  to  act,  the  heart  con- 
tinues to  beat  without  cessation.  The  volun- 
tary muscles,  on  the  other  hand,  are  such  ae  are 
used  only  when  we  wish  or  will  to  use  them — • 

as  the  muscles  of  the  hand  or  arm  (Figs.  11  and  12).     (Read  Note  1  ) 

1.  The  Perfection  of  the  Human  Hand. — "Gordy  counts  thirty-four 
distinct  movements  of  the  hand,  and  if  we  include  the  combinations  of  these 
different  movements,  we  shall  reach  a  much  higher  number.  Properly  speak- 
ing, the  hand  belongs  to  man  alone,  and  its  form  does  not  permit  us  to  con 
sider  it  an  organ  of  locomotion,  as  is  the  case  with  certain  animals  most  closely 
resembling  man.  Nothing  gives  a  moxe  complete  idea  of  the  perfection  of  the 


PIG.  11.— A,  Biceps  mus- 
cle of  the  arm ;  B,  C, 
Its  tendons. 


3.  Arrangement  of  the  muscles?    Their  action?    Flexion  and  extension  ?    Action  of  the 
muscles  when  we  stand  erect? 

4.  Kinds  of  muscles?    The  voluntary?    Involuntary?    The  heart?    Give  the  example. 
The  hand?    Arm? 


THE    MUSCLES. 


5.  The  Tendons. — Tendons,  or  sinews,  are  the  extremities  of 
muscles,  and  are  firmly  fastened  upon  the  bone.     They  are  very 


B 


PIG.  12  shows  the  muscles  and  tendons  of  the  hand  ;  A  showing  the  palm,  B  the  back  of  the 
hand.  These  numerous  muscles  and  tendons  form  a  very  complicated  piece  of  mechan- 
ism, and  heip  to  give  to  the  hand  its  marvellous  dexterity  and  flexibility. 

mechanism  of  the  hand  than  the  execution  of  instrumental  music.  Examine 
an  artist  while  he  plays  the  violin.  His  fingers  rest  upon  the  strings  so  as  to 
leave  them  exactly  of  the  length  necessary  for  the  tones  they  are  to  give.  The 
half  of  a  millimetre,  more  or  less,  greatly  changes  the  accuracy  of  the  note  ; 
and  a  chord  a  millimetre  out  of  place  produces  a  note  which  even»the  unprac- 
tised ear  can  recognize  as  false.  But  the  fingers  fall  upon  the  strings  at  pre- 
cisely the  point  required.  They  run  over  them,  succeeding  each  other  with 
giddy  rapidity,  following  every  imaginable  combination,  and  yet  the  hand 
gliding  over  the  instrument  incessantly  changes  its  position.  Sometimes  a 
single  finger  produces  an  isolated  note  ;  sometimes  two  or  three  act  simulta- 
neously to  produce  a  concord  ;  while  a  fourth,  striking  a  string  with  increasing 
rapidity,  produces  a  trill  which  rivals  the  nightingale.  Add  to  all  these  the 
modifications  necessary  to  swell  the  sound  or  let  it  die  away — all,  in  a  word, 
that  constitutes  musical  expression,  and  it  will  be  admitted  that  this  mechan- 
ism is  allied  to  the  wonderful,  and  that  it  surpasses  the  most  perfect  produc- 
tions of  human  art."  A  further  idea  of  the  rapidity  of  the  hand's  movements 
is  given  in  the  playing  of  a  skilful  pianist,  whose  hands,  oftenest  occupied 
together,  produce  on  an  average  six  to  eight  notes  at  a  time,  or  about  640  notes 
in  a  minute  in  medium  time,  and  960  notes  in  extremely  quick  time. — Tht 
Wonders  of  ike  Muman  Body. 


34 


THE  MUSCLES. 


strong,  and  of  a  silvery  whiteness.  They  may  be  felt  just  beneath 
the  skin,  in  certain  parts  of  the  body,  when  the  muscles  are  being 
used,  as  at  the  bend  of  the  elbow  or  knee.  The  largest  tendon  of 
the  body  is  that  which  is  inserted  into  the  heel,  called  the  tendon 
of  Achilles,  after  th  e  hero  of  the  Grecian  poet,  the  fable  relating  that 
it  was  at  this  point  that  he  received  his  death-wound,  no  other  part  of 
his  body  being  vulnerable.  (Fig.  13).  The  muscles  in  the  front  part 
of  the  thigh  unite  to  form  a  single  and  very 
powerful  tendon,  and  enclose  a  small  bone 
called  the  knee-pan,  which,  acting  like  a 
pulley,  greatly  increases  their  power,  and  at 
the  same  time  protects  the  front  of  the  knee- 
joint  (Fig.  14). 

6.  Muscular  Contraction. — The  muscles, 
when  acted  upon  by  the  appropriate  stimu- 
lus, contract,  or  so  change  their  shape,  that 
their  extremities  are-  brought  nearer  together. 
The  bending  of  the  arm,  or  of  a  finger,  is 
effected  in  this  manner,  by  the  will ;  but  the 
will  is  not  the  only  means  of  producing  this 
effect.  Electricity,  a  sharp  blow  over  a  mus- 
cle, and  other  stimuli,  also  cause  it.  Con- 
traction does  not  always  cease  with  life.  In 
man,  after  death  from  cholera  automatic 
movements  of  hands  and  feet  have  been  ob- 
served, lasting  not  less  than  an  hour.  In 

certain  cold-blooded  animals,  as  the  turtle,  contraction  has  been 
known  to  take  place  for  several  days  after  the  head  has  been  cut  off 
7.  The  property  which,  in  muscle,  enables  these  movements  to 
take  place  is  called  contractility.  If  we  grasp  a  muscle  while  in 
exercise  (for  example,  the  large  muscle  in  the  front  of  the  arm),  we 
notice  the  alternate  swelling  and  decrease  of  the  muscle,  as  we 
move  the  forearm  to  and  fro.  It  was  at  one  time  supposed  that  the 

5.  What  are  the  tendons  or  sinews?    Their  strength?    Color?    Location?    Tendon  oi 
Achilles?    The  fable?    Muscles  of  the  leg? 

6.  Contraction  of  the  muscles?    Bending  of  the  arm  or  finger?    Other  agencies?    Auto- 
matic movements  ?    In  cold-blooded  animals  ? 

7.  Contractility?   Give  the  illustration.    What  was  supposed?    What  is  the  easel 


FIG.  13. 
LOWER  PORTION  OF  THE  LEO. 


THE   MUSCLES.  85 

muscle  actually  increased  in  volume  during  contraction.  This, 
however,  is  not  the  case ;  for  the  muscle,  while  gaining  in  thickness, 
loses  in  length  in  the  same  proportion ;  and  thus  the  volume  re- 
mains the  same  in  action  and  at  rest. 


FICL  14.— VIEW  OF  KNEE-JOINT.    A,  Thigh  bone ;  B,  Knee-pan ;  C,  D,  Leg  bones. 

8.  Contraction  is  not  the  permanent,  or  normal,  state  of  a  mus- 
cle.    It  cannot  long  remain  contracted,  but  after  a  time  it  wearies, 
and  is  obliged  to  relax.     After  a  short  rest,  it  can  then  again  con- 
tract.    It  is  for  this  reason  that  the  heart  can  beat  all  through  life, 
night  and  day,  by  having,  as  we  shall  hereafter  see,  a  brief  interval 
of  rest  between  successive  contractions.     For  the  same  reason,  it  is 
more  fatiguing  to  stand  for  any  great  length  of  time  in  one  position, 
than  to  be  walking  for  the  same  period. 

9.  Relative  Strength  of  Animals. — The  amount  of  muscular 
power  which  different  animals  can  exert,  has  been  tested  by  experi- 
ment.    By  determining  the  number  of  pounds  which  an  animal  can 
drag  upon  a  level  surface,  and  afterward  comparing  that  with  its 
own  weight,  we  can  judge  of  its  muscular  force.     It  is  found  that 
man  is  able  to  drag  a  little  less  than  his  own  weight.     A  draught- 
horse  can  exert  a  force  equal  to  about  two-thirds  of  his  weight. 

8.  What  further  in  relation  to  contraction?    Weariness  of  a  muscle?    Beating  of  the 
heart?    Standing  and  walking? 

9.  Muscular  power  of  animals?   How  tested?  Man's  power?  Horse's?  The  comparison! 


36  THE   MUSCLES. 

The  horse,  therefore,  though  much  heavier  than  man,  is  relatively 
not  so  powerful. 

10.  Insects  are  remarkable  for  their  power  of  carrying  objects 
larger  and  heavier  than  themselves.     Many  of  them  can  drag  ten, 
and  even  twenty  times  their  weight.     Some  of  the  beetles  have 
been  known  to  move  bodies  more  than  forty  times  their  own  weight. 
So  far,  therefore,  from  it  being  a  fact  that  animals  have  strength  in 
proportion  to  their  weight  and  bulk,  the  reverse  of  that  statement 
seems  to  be  the  law. 

11.  Physical  Strength. — The  difference  in  strength,  as  seen  in 
different  individuals,  is  not  due  to  any  original  difference  in  their 
muscles.     Nature  gives  essentially  the  same  kind  and  amount  of 
muscles  to  every  healthy  person,  and  the  power  of  one,  or  the  weak- 
ness of  another,  arises,  in  great  part,  from  the  manner  in  which 
these  organs  are  used  or  disused. 

12.  Many  authors  complain  of  the  physical  degeneracy  of  men  at 
the  present  day,  as  compared  with  past  generations.     There  is  room 
for  doubt  as  to  the  correctness  of  this  statement.     Certain  experi- 
ments have  recently  been  made  with  the  metallic  armor  worn  seven 
hundred  years  ago,  by  which  it  is  found  that  any  man,  of  ordinary 
height  and  muscular  development,  can  carry  the  armor  and  wield 
the  weapons  of  an  age  supposed  to  be  greatly  our  superior  in  strength. 
"When  we  consider  that  in  those  days  only  very  strong  men  could 
endure  the  hardships  of  soldier-life,  it  is  fair  to  suppose  that  our  age 
has  not  so  greatly  degenerated  in  respect  to  physical  strength. 

13.  Importance  of  Exercise. — Action  is  the  law  of  the  living 
body.     Every  organ  demands  use  to  preserve  it  in  full  vigor,  and  to 
obtain  from  it  its  best  services.     The  value  of  that  training  of  the 
mind,  which  we  call  education,  is  everywhere  recognized.     The 
child  is  early  put  to  school;  and  for  many  years  continues  to  study, 
in  order  that  his  brain,  which  is  the  great  centre  of  mental  power, 
may  act  healthfully  and  powerfully.     It  is  important  that  the  mus- 
cles, also,  should  receive  their  education  by  exercise.     This  is  true, 

10.  Power  of  insects?    Beetles?    Give  the  conclusion. 

11.  Difference  in  strength  of  individuals?    How  caused? 

12.  Complain  tin  relation  to  degeneracy?    How  true?    How  determined  by  armor?    The 
feir  supposition? 

13.  Action?    Use  of  organs?    Training  of  the  mind ?    The  child's  brain ?    Education  ol 
the  body? 


THE   MUSCLES.  37 

not  only  in  respect  to  children,  but  also  of  adults  whose  occupation 
confines  them  within  doors,  and  requires  chiefly  brain-work. 

14.  Persons  who  are  engaged  in  manual  labor  in  the  open  air 
obtain  all  the  exercise  necessary  for  bodily  health  in  their  regular 
business :  their  need  is  more  likely  to  be  a  discipline  or  exercise  of 
the   mind.     A   perfect   business  of   life,  therefore,  would  be  one 
which  would   combine   both   physical  and  mental  labor  in  their 
proper  proportions.     If  such  a  business  were  possible  for  all  the 
human  race,  life  would  thereby  be  vastly  prolonged.     Such,  in  fact, 
is  to  a  large  extent  the  occupation  pertaining  to  one  period  of  life — 
childhood.     One  part  of  the  time  is  given  to  study,  and  another 
to  muscular  education  by  means  of  games  and  sports.     The  restless- 
ness and  playfulness  of  children  is  not  only  natural  but  beneficial. 

15.  The  Effects  of  Exercise. — Exercise  consists  in  a  well-regu, 
lated  use  of  the  voluntary  muscular  system.     The  effects,  however, 
are  not  limited  to  the  parts  used.     Other  organs,  which  are  not 
under  the  control  of  the  will,  are  indirectly  influenced  by  it.     The 
heart  beats  more  rapidly,  the  skin  acts  more  freely,  the  temperature 
rises,  the  brain  is  invigorated,  and  the  appetite  and  power  of  diges- 
tion are  increased.     An  increased  exhalation  from  the  lungs  and 
skin  purifies  the  current  of  the  circulation,  and  the  body  as  a  whole 
thrives  under  its  influence.     (Read  Note  2. ) 

2.  Health  in  Athletic  Exercise. — "  Health  is  perpetual  youth — that  is, 
a  state  of  positive  health.  Merely  negative  health,  the  mere  keeping  out  of 
the  hospital  for  a  number  of  years,  is  not  health.  Health  is  to  feel  the  body  a 
luxury,  as  every  vigorous  child  does ;  as  the  bird  does  when  it  shoots  and 
quivers  through  the  air,  not  flying  for  the  sake  of  the  goal,  but  for  the  sake  of 
flight ;  as  the  dog  does  when  he  scours  madly  across  the  meadows,  or  plunges 
into  the  muddy  blissfulness  of  the  stream ;  but  neither  bird,  nor  dog,  nor 
child  enjoys  his  cup  of  physical  happiness — let  the  dull  or  the  worldly  say 
what  they  will — with  a  felicity  so  cordial  as  the  educated  palate  of  conscious 
manhood.  To  'feel  one's  life  in  every  limb,'  this  is  the  secret  bliss  of  which 
all  forms  of  athletic  exercise  are  merely  varying  disguises  ;  and  it  is  absurd  to 
say  that  we  cannot  possess  this  when  character  is  mature,  but  only  when  it  is 
half  developed.  As  the  flower  is  better  than  the  bud,  so  should  the  fruit  be 
better  than  the  flower." 


14.  Work  in  the  open  air?    A  perfect  business?    The  consequence  of  universal  perfect 
business  ?    Occupation  of  children  ? 

15.  In  what  does  exercise  consist?    Effects  of  it? 


38  THE   MUSCLES. 

16.  The  first  effects  of  exercise,  however,  are  upon  the  muscles 
themselves;  for  by  use  they  become  rounded  out  and  firm,  and  increase 
in  power.     If  we  examine  a  muscle  thus  improved  by  exercise,  we 
find  that  its  fibres  have  become  larger  and  more  closely  blended  to- 
gether, that  its  color  is  of  a  darker  red,  and  that  the  supply  of 
blood-vessels  has  increased.      Without  exercise  the  muscle  appears 
thin,  flabby,  and  pale.     On   the   other  hand,  excessive   exercise, 
without  sufficient  relaxation,  produces  in  the  muscle  a  condition  not 
very  different  from  that  which  follows  disuse.      The  muscle  is  worn 
out  faster  than  nature  builds  it  up,  and  it  becomes  flabby,  pale,  and 
weak. 

17.  Violent  exercise  is  not  beneficial ;   and  spasmodic  efforts  to 
increase  the  muscular  strength  are  not  calculated  to  secure  such  a 
result.      Strength  is  the  result  of  a  gradual  growth,  and  is  most 
surely  acquired  if  the  exercise  be  carried  to  a  point  short  of  fatigue, 
and  after  an  adequate  interval  of  rest.     To  gain  the  most  beneficial 
results,  the  exercise  should  be  at  regular  hours  and  during  a  regular 
period,  the  activity  and  the  time  varying  with  the  strength  of  the 
individual,  and  carefully  measured  by  it.     (Read  Note  3. ) 

3.  The  Ill-effects  of  Over-exertion. — "  It  should  be  recollected  that 
the  action  of  the  muscles  has  limits,  as  well  as  that  of  every  other  organ  of 
the  body.  The  muscles  and  the  heart  may  be  taxed  too  severely,  and  perma- 
nent derangements  may  be  produced  by  overtaxing  the  human  body.  The 
ancient  gymnasts  among  the  Greeks  are  said  to  have  become  prematurely  old, 
and  the  clowns  (or  acrobats)  and  athletes  of  our  own  days  suffer  from  the 
severe  strain  put  upon  their  muscular  systems. "  The  effects  of  boat-racing  in 
England  have  been  thus  described  by  Dr.  Skey,  an  eminent  surgeon :  "  The 
men  look  utterly  exhausted.  Their  white  and  sunken  features  and  pallid  lips 
show  serious  congestion  of  the  heart  and  lungs,  and  the  air  of  weakness  and 
lassitude  makes  it  a  marvel  how  such  great  exertion  should  have  been  so  nobly 
undergone.  "We  have  repeatedly  seen  the  after  ill-effects — spitting  of  blood, 
congested  lungs,  and  weakness  of  the  heart  from  over-distension."  "  Persons 
should  neither  walk,  run,  leap,  or  play  at  any  game,  to  the  extent  of  produc- 
ing permanent  or  painful  exhaustion.  All  exercise  should  be  attended  with 
pleasurable  feelings  ;  and  when  pain  is  produced  by  proper  exercise,  those  who 
suffer  should  rather  seek  medical  advice  than  persevere  in  exercise. " — Lankes- 
ter's  Manual  of  Health. 

16.  General  effect  upon  the  muscles?    Special  effect?    Effects  of  inaction?    Of  excessive 
exercise  ? 

17.  Of  violent  and  spasmodic  efforts  ?  Strength,  how  attained  ?  Give  the  particulars. 


THE   MUSCLES. —  39 


18.  Different  Modes  of  Exercise. — There  are  very  few  who 
have  not  the  power  to  walk.     There  is  required  for  it  no  expensive 
apparatus,  nor  does  it  demand  a  period  of   preliminary  training. 
Walking  may  be  called  the  universal  exercise.     With  certain  foreign 
nations,  the  English  especially,  it  is  a  very  popular  exercise,  and  is 
practised  habitually   by  almost  every   class  of    society;    by  the 
wealthy  who  have  carriages,  as  well  as  by  those  who  have  none ;  by 
women  as  well  as  by  men. 

19.  Eunning,  leaping,  and  certain  other  more  rapid  and  violent 
movements,  are  the   forms  of  exercise   that  are  most  enjoyed  in 
childhood.     Fcr  the  child,  they  are  not  too  severe,  but  they  may  be 
so  prolonged  as  to  become  injurious.     Instances  have  been  recorded 
where  sudden  death  has  resulted  after  violent  playing,  from  overtax- 
ing the  heart :   for  example,  we  have  the  case  of  a  young  girl  who, 
while  skipping  the  rope,  and  endeavoring  to  excel  her  playmates  by 
jumping  the  greatest  number  of  times,  fell  dead  from  rupture  of  the 
heart. 

20.  Carriage-riding  is  particularly  well  suited  to  invalids  and 
persons  advanced  in  life.       Horseback  exercise  brings  into  use  a 
greater  number  of  muscles  than  any  other  one  exercise,  and  with  it 
there  is  an  exhilaration  of  feeling  which  refreshes  the  mind  at  the 
same  time.      It  is  one  of  the  manliest  of  exercises,  but  not  less 
suitable  for  women  than  for  men.    To  be  skilful  in  riding,  it  should 
be  begun  in  youth. 

21.  For  those  who  live  near  streams  or  bodies  of  water,  there  are 
the  delightful  recreations  of  boating,  swimming,  and  skating.    Cer- 
tain of  these  exercises  have  a  practical  importance  aside  from  and 
above  their  use  in  increasing  the  physical  vigor.     This  is  especially 
true  of  boating  and  swimming,  since  they  are  often  the  means  of 
saving  life.      Practice  in  these  exercises  also  teaches  self-reliance, 
courage,  and  presence  of  mind.    Persons  who  have  become  proficient 
in  these  vigorous  exercises  are  generally  the  ones  who,  in  times  of 
danger,  are  the  quickest  to  act  and  the  most  certain  to  do  so  with 
judgment. 

18.  What  may  walking  be  called?   What  further  is  said  of  walking? 

19.  What  is  said  of  running,  and  other  like  movements?    What,  as  related  to  childhood? 
What  instances  are  alluded  to  ?    Example  ? 

20.  Carriage-riding?    Horseback -riding? 

21.  Boating,  swimming,  and  skating? 


40  THB   MUSCLES. 

22.  Physical  Culture. — That  form  of  exercise  which  interests 
and  excites  the  mind,  will  yield  the  best  results ;   but  to  some  per- 
sons no  kind  of  exertion  whatever  is,  at  first,   agreeable.     They 
should,  nevertheless,  make  a  trial  of  some  exercise,  in  the  expecta- 

,  tion  that,  as  they  become  proficient  in  it,  it  will  become  more 
pleasant.  In  exercise,  as  many  sets  of  muscles  should  be  employed 
as  possible,  open-air  exercise  being  the  best.  Parlor  gymnastics, 
and  the  discipline  of  the  gymnasium  are  desirable,  but  they  should 
not  be  the  sole  reliance  for  physical  culture.  No  in-door  exercise; 
however  excellent  in  itself,  can  fill  the  place  of  hearty  and  vigorous 
activity  in  the  open  air.  (Read  Note  4.) 

23.  Excessive  Exercises. — If  neglect  of  exercise  is  injurious, 
so  also  is  the  excess  of  it.      Violent  exertions  do  harm ;  they  often 
cause  undue  strain,  and  even  lasting  injury  to  some  part  of  the  body. 
For  this  reason  the  spirit  of  rivalry  which  leads  to  tests  of  endur- 
ance and  feats  of  strength  should  be  discouraged.     Those  trials  of 
the  muscles,  especially,  which  are  supposed  to  demand  "  training," 
should  not  be  encouraged.     Training,  it  is  true,  can  produce  a  re- 
markable muscular  development,  so  that  nearly  every  muscle  of  the 
limbs  is  as  large  and  corded  as  the  arm  of  a  blacksmith;  but  it  is 
too  often  at    the  expense   of   some  internal,  vital   organ.     Large 
muscles  are  not  a  certain  index  of  good  health.    It  was  well  known 
by  the  ancients  that  athletes  of  their  day  were  short-lived,  notwith- 
standing the  perfection  of  the   physical   training  then  employed. 

4.  Exercise  should  be  Pleasurable. — "  The  world  seldom  attaches 
much  value  to  things  which  are  plain  and  easily  understood.  The  dervish  in 
the  Eastern  allegory,  well  aware  of  this  weakness,  knew  that  it  would  be  in 
vain  to  recommend  the  sultan,  for  the  cure  of  his  disease,  simply  to  take 
exercise.  He  knew  that  mankind  in  general  required  to  be  cheated,  gulled, 
cajoled,  even  intc  doing  that  which  is  to  benefit  themselves.  He  did  not, 
therefore,  tell  the  sultan,  who  consulted  him,  to  take  exercise,  but  he  said  to 
him  :  *  Here  is  a  ball,  which  I  have  stuffed  with  certain  rare,  costly,  and 
precious  medicinal  herbs.  Your  highness  must  take  this  bat,  and  with  it  beat 
about  this  ball  until  you  perspire  very  freely.  You  must  do  this  every  day.' 
His  highness  did  so,  and  in  a  short  time  the  exercise  of  playing  at  bat  and  ball 
with  the  dervish  cured  his  malady." — First  Help. 


22.  What  kind  of  exercise  yields  the  best  results  ?    What  advice  is  given  ? 

23.  Physical  culture  among  the  ancients?    In  Greece?    In  schools  and  colleges  at  the 
present  time  ?    Result  to  the  body  and  mind  ? 


THE   MUSCLES.  41 

* 

When  a  person  overtasks  the  heart,  or,  in  other  words,  "  gets  out  of 
breath,"  he  should  regard  it  as  a  signal  to  take  rest.  It  is  well 
known  that  both  horses  and  men,  after  having  been  brought  into 
"  condition "  for  competitive  trials,  soon  lose  the  advantages  of 
their  training  after  the  occasion  for  it  has  passed^ 

24.  Gymnastic  Exercises  fop  Schools  and  Colleges. — In  the 
system  of  education  among  the  ancients,  physical  culture  predom- 
inated.    In  ancient  Greece,  physical  exercises  in  schools  were  pre- 
scribed and  regulated  by  law,  and  hence  these  schools  were  called 
gymnasia.      At  the  present  time,  on  the  contrary,  this  culture  is 
almost   wholly   unknown,  as   a  part  of   the  course  of   education, 
in  our  schools,  and  but  to  a  limited  extent  in  colleges.     In  a  few  of 
our  schools,  however,  physical  exercises  have  been  introduced,  with 
manifest  advantage  to  the  students,  and  they  form  a  part  of  the 
regular  curriculum  of  exercises, — as  much  so  as  the  recitations  in 
geography,  grammar  or  Greek.     The  good  effect  of  the  experiments, 
as  shown  in  improved  scholarship  as  well  as  increased  bodily  vigor, 
in  the  institutions  where  the  plan  has  been  tried,  will,  it  is  hoped, 
lead  to  its  universal  adoption.    We  should  then  hear  less  frequently 
of  parents  being  obliged  to  withdraw  their  children  from  school,  be- 
cause they  become  exhausted  or,  perchance,  have  lost  their  health 
from  intense  and  protracted  mental  application. 

25.  Were  gymnastics  more  common  in  our  educational  institu- 
tions we  should  not  so  often  witness  the  sad  spectacle  of  young  men 
and   women   leaving   our   colleges   and   seminaries,  with  finished 
educations  it  may  be,  but  with  constitutions  so  impaired  that  the 
life  which  should  be  devoted  to  the  accomplishment  of  noble  pur- 
poses must  be  spent  in  search  of  health.     Spinal  curvatures,  which, 
according   to   the    experience   of   physicians,    are   now   extremely 
frequent,  especially  among  women,  would  give  place  to  the  steady 
gait  and  erect  carriage  which  God  designed  his  human  creatures 
should  maintain.     (Read  Notes  5  and  6. ) 

5.  Health  and  Strength/are  not  always  Identical.— "  Health  and 
strength  are  not  synonymous  jerms.  A  person  may  have  great  strength  in  his 
limbs,  or  in  certain  muscles  apout  the  body,  but  really  not  have  good  health. 
It  is  altogether  a  mistaken  idea  to  suppose  that  physical  exercises  have  fol 

24.  The  result  of  gymnastics  in  our  colleges  and  other  institutions  of  learning? 

25.  Were  gymnastics  more  common  ?    To  what  are  spinal  curvatures  due  ? 


42  THE   MUSCLES. 

26.  All  the  exercises  necessary  for  the  proper  development  of  the 
body  may  be  obtained  from  the  use  of  a  few  simple  contrivances,  that 
every  one  can  have  at  home  at  little  cost — less  by  far  than  that  of 
useless  toys.  Many  of  these  may  be  made  available  in  the  parlor  or 
chamber,  though  all  exercises  are  far  more  useful  in  the  open  air.  A 
small  portion  of  the  day  thus  spent  will  afford  agreeable  recreation,  as 
well  as  useful  exercise.  The  Indian  club,  the  wand,  the  ring  and 
the  light  wooden  dumb-bell  are  among  the  articles  devised  to  assist 
in  the  smooth  performance  of  class  drill.  Pleasant  music  timed  to 
the  movements  of  the  drill  is  a  further  aid,  just  as  martial  music  by 
a  good  band  is  a  great  help  to  soldiers  on  the  march. 

their  sole  object  the  attainment  of  strength.  There  are  other  tissues  and  organs 
in  the  human  system  besides  the  muscular ;  and  the  healthy  action  of  the 
lungs  and  the  stomach  is  far  more  important  than  great  strength  in  the  arms, 
legs,  or  the  back.  It  is  here,  in  this  general  exercise  of  all  the  muscles  and 
parts  of  the  body,  that  a  well-regulated  system  of  gymnastics  has  its  great  ex- 
cellence. It  aims  to  produce  just  that  development  of  the  human  system  upon 
which  good  health  is  permanently  based,  described  by  a  distinguished  writer 
as  follows : — '  Health  is  the  uniform  and  regular  performance  of  all  the 
functions  of  the  body,  arising  from  the  harmonious  action  of  all  its  parts,' — a 
physical  condition  implying  that  all  are  sound,  well-fitting,  and  well-matched. 
Some  minds  do  not  look  far  enough  into  life  to  see  this  distinction,  or  to  value 
it  if  seen  ;  they  fix  their  eyes  longingly  upon  strength — upon  strength  now,  and 
seemingly  care  not  for  the  power  to  work  long,  to  work  well,  to  work  successfully 
hereafter,  which  is  health." — Dr.  Nathan  Allen  on  Physical  Culture. 

6.  On  Recreation. — "Our  whole  method  of  amusements,  especially  for 
the  young,  should  be  reformed.  Gas-light  should  yield  to  daylight,  night 
vapors  in  heated  and  close  rooms  should  give  way  to  fresh  air  under  the  open 
heavens,  and  our  young  people  should  be  brought  up  to  work  and  play  under 
the  ministry  of  that  great  solar  force  which  is  the  most  benign  and  god-like 
agent  known  to  men.  Ardent  spirits  and  tobacco  should  be  given  up,  and  in 
their  stead  genial  exercise  of  riding,  gymnastics,  and  the  dance,  with  music  and 
all  beautiful  arts,  should  be  employed  to  stir  the  languid  powers  and  soothe 
the  troubled  affections.  The  old  Greeks  taught  music  and  gymnastics  as  parts 
of  education,  and  Plato,  in  urging  the  importance  of  these,  still  maintains  that 
the  soul  is  superior  to  the  body,  and  religion  is  the  crown  of  all  true  culture. 
Why  may  not  Christian  people  take  as  broad  a  position  on  higher  ground,  and 
with  a  generous  and  genial  culture  associate  a  faith  that  is  no  dreamy  sentiment 
or  ideal  abstraction,  but  the  best  power  of  man  and  the  supreme  grace  of  God." 
— Rev.  Dr.  Osgood  on  "  The  Skeleton  in  Modern  Society." 

26.  Proper  exercise  at  home  ?    How  obtained ?    What  as  to  regularity? 


THE   MUSCLES. 


Home  Gymnastics. — This  is  perhaps  a  better  name  than 
parlor  gymnastics  for  those  exercises  which  may  be  practiced  by 
individuals  at  home.  Apparatus  of  various  forms,  and  generally 
simple  in  construction,  has  been  devised,  and  may  be  had  at  small 
cost.  It  can  be  set  up  in  almost  any  room  in  the  house.  In  some 
of  these  appliances  cords  or  bands  of  rubber  and  pulleys  are  used ; 
in  others,  simply  weights  with  cords  and  pulleys,  without  elastic 
material.  The  latter  kind  is  better,  inasmuch  as  the  movement  is 
even  and  the  action  of  the  muscle  steady,  while  with  rubber  bands 
the  farther  they  are  stretched  the 
greater  is  the  exertion.  No  appa- 
ratus yet  invented  answers  its  pur- 
pose so  well  as  the  "  chest  weight" 
(see  Fig.  15).  By  its  use  all  the 
prominent  muscles  of  the  body  are 
easily  exercised.  No  instruction  is 
necessary  and  the  space  occupied  is 
easily  spared.  A  person  is  obliged 
only  to  grasp  the  handles  and  then 
follow  the  simple  directions  given 
to  bring  into  action  whatever  mus- 
cles or  groups  of  muscles  he  wishes 
to  exercise.  The  weight  can  be 
changed  to  suit  the  strength  of  the 
one  exercising.  Illustrations  show- 
ing a  few  of  the  positions  and  move- 
ments that  are  recommended  with 
one  of  the  chest  weights,  are  given 
in  the  Appendix,  page  304. 

28.  In  addition  to  the  movements  mentioned  many  others  might 
fee  employed,  varying  with  the  particular  muscles  or  parts  that  re- 
quire to  be  exercised.  Combinations  of  cords  and  pulleys  suitable 
for  particular  cases  can  be  made,  and  the  resistance  of  the  weights 
adjusted  to  the  needs  of  the  weakly  and  the  young,  as  well  as  to  the 
most  robust.  These  exercises  are  by  no  means  limited  to  those 


FIG.  15. 
THE  "CHEST  WEIGHT.' 


27.  What  kind  of  apparatus  is  recommended  for  home  gymnastics?    Why?    Describe 
advantages  of  the  "chest  weight." 


44  THE   MUSCLES. 

who  are  in  health  and  who  resort  to  them  as  a  relaxation  from  long 
study  or  sedentary  occupations.  Persons  who  are  not  strong,  who 
cannot  take  advantage  of  school  drill,  or  who  are  convalescing  from 
sickness,  may,  under  suitable  conditions,  be  especially  benefited  by 
them.  Not  all  the  movements  should  be  tried  at  first,  but,  on  the 
contrary,  there  should  be  a  careful  selection  of  two  or  three  that 
seem  to  be  best  suited  to  the  needs  of  the  patient.  These  exercises 
must  also  be  undertaken  gradually  and  increased  in  proportion  to 
the  ability  of  each  individual.  There  should  be  some  degree  of 
uniformity  as  to  the  time  of  day  as  well  as  to  the  form  and  dura- 
tion of  the  gymnastic  effort  engaged  in.  Kemember  always  to  stop 
short  of  the  point  where  manifest  fatigue  begins  to  be  felt,  regard- 
less of  the  shortness  or  the  length  of  the  time.  The  key-note  to 
beneficial  home  exercise  is  to  put  into  use  as  many  muscles  as  is 
proper  and  safe,  without  bringing  about  a  feeling  of  exhaustion.  If 
exhaustion  is  produced,  the  exercise  passes  into  violence,  and  as  we 
have  formerly  learned,  violence  is  harmful.  It  must  be  remem- 
bered that  these  movements  not  only  develop  the  parts  named, 
but  each  movement  exercises  many  other  muscles  at  the  same  time. 
In  Figs.  9  and  10  (App.)  always  take  a  deep  breath  b'efore  each 
motion.  Then  the  pressure  of  the  filled  lungs,  together  with  the  ac- 
tion of  the  muscles,  will  more  quickly  widen  and  deepen  the  thorax. 

29.  Rest. — We  cannot  always"TJe"5ctfve 7"after  -labor  we  must 
rest.     "We  obtain  this  rest  partly  by  suspending  all  exertion,  as  in 
sleep,  and  partly  by  a  change  of  employment.     It  is  said  that  Alfred 
the  Great  recommended  that  each  day  should  be  divided  in  the  fol- 
lowing manner  :  "  Eight  hours  for  work,  eight  hours  for  recreation, 
and  eight  hours  for  sleep."     This  division  of  time  is  as  good  as  any 
that  could  now  be  made,  if  it  be  borne  in  mind  that,  when  the 
work  is  physical,  the  time  of  recreation  should  be  devoted  to  the 
improvement  of   the   mind;   and  when   mental,  we   should   then 
recreate  by  means  of  physical  exercise. 

30.  During  sleep,  all  voluntary  activity  ceases,  the  rapidity  of 
the  circulation  and  breathing  diminishes,  and  the  temperature  of 

29.  Need  of  repose?    How  do  we  obtain  rest?    Alfred  the  Great?    The  eight  hour  divi- 
sion of  time  ? 

30.  Cessation  of  voluntary  activity?     Temperature  of  the  body?    Consequence?     Body 
and  mind  during  sleep  ?    Nutrition?    Describe  It.    Consequence  of  insufficient  sleep? 


THE    MUSCLES.  45 

the  body  falls  one  or  two  degrees.  In  consequence,  the  body 
needs  warmer  coverings  than  during  the  hours  of  wakefulness. 
During  sleep,  the  body  seems  wholly  at  rest,  and  the  mind  is  also 
inactive,  if  we  except  those  involuntary  mental  wanderings  which 
we  call  dreams.  Nevertheless  a  very  active  and  important  physical 
process  is  going  on.  Nutrition,  or  the  nourishing  of  the  tissues, 
now  takes  place.  While  the  body  is  in  action,  the  process  of  pull- 
ing down  predominates,  but  in  sleep,  that  of  building  up  takes 
place  more  actively.  In  this  way  we  are  refreshed  each  night,  and 
prepared  for  the  work  and  pleasures  of  another  day.  If  sleep  is 
insufficient,  the  effects  are  seen  in  the  lassitude  and  weakness 
which  follow.  Wakefulness  is  very  frequently  the  forerunner  of 
insanity,  especially  among  those  who  perform  excessive  mental 
labor. 

31.  All  persons  do  not  require  the  same  amount  of  sleep,  but  the 
average  of  men  need  from  seven  to  nine  hours.     There  are  well- 
authenticated  cases  where  individuals  have  remained  without  sleep 
for   many   days   without   apparent   injury.     Frederick   the   Great 
required  only  five  hours  of  sleep  daily,  and  Bonaparte  could  pass 
days  with  only  a  few  hours  of  rest.    But  this  long-continued  absence 
of  sleep  is  attended  with  danger.     After  loss  of  sleep  for  a  long 
psriod,  in  some  instances,  stupor  has  come  on  so  profoundly,  that 
there  has  been  no  awaking. 

32.  There  are  instances  related  of  sailors  falling  asleep  on  the 
gun-deck  of  their  ships  while  in  action.     On  the  retreat  from  Mos- 
cow, the  French  soldiers  would  fall  asleep  on  the  march,  and  could 
only  be  aroused  by  the  cry,  "  The  Cossacks  are  coming ! "    Tortured 
persons  are  said  to  have  slept  upon  the  rack  in  the  intervals  of  their 
torture.     In  early  life,  while  engaged  in  a  laborious  country  prac- 
tice, the    writer   not    unfrequently    slept    soundly   on   horseback. 
These  instances,  and  others,  show  the  imperative  demand  which 
nature  makes  for  rest  in  sleep. 

33.  Alcohol  and  Strength.— Alcohol,  a  substance  to  be  fully 
described  in  our  subsequent  chapter  on  Food  and  Drink,  merits 


81.  Amount  of  sleep  for  different  persons?    Cases?    Frederick  the  Great?    Bonaparte? 
Instances  of  long  deprivation  of  sleep  ? 
32.  Instances  of  sailors?    French  soldiers  ?    During  torture ? 


46  THE   MUSCLES. 

consideration  at  this  point  by  reason  of  the  mistaken  views  held 
by  many  as  to  its  beneficial  effects  upon  the  muscles  when  they 
are  put  into  vigorous  use,  and  especially  into  daily  manual  labor. 
It  is  well  known  that  for  generations  it  was  thought  to  be  essential 
to  every  army  and  navy  of  the  civilized  world  that  "grog" — which 
contains  alcohol — should  be  regularly  issued  to  the  hard-worked 
soldier  and  sailor,  especially  when  they  were  in  the  actual  service  of 
war.  To  the  slaves,  also,  on  many  plantations,  during  the  days  of 
slavery  in  this  country,  a  daily  ration  of  rum  was  given  out  in  the 
busy  seasons,  in  the  belief  that  thus  better  results,  in  regard  to  the 
amount  of  muscular  labor,  were  secured.  So  too,  in  nearly  every 
walk  of  life  where  hard  muscular  labor  was  demanded,  a  similar 
belief  and  practice  commonly  prevailed,  and  some  form  of  alcohol 
was  resorted  to  as  a  trusty  servant  whenever  any  great  or  unusual 
amount  of  labor  was  to  be  called  forth. 

34.  How  Alcohol  affects  the  Muscles. — The  scientific  progress 
of  recent  years,  however,  has  put  the  question  in  a  different  light, 
and  it  is  now  the  commonly  received  view  of  scientific  men  that 
the  benefits  to  labor  derived  from  alcohol  were  apparent  and  not 
real.     Alcohol  adds  nothing  to  our  bodily  energy ;  it  may  spur  up 
the  muscles  to  a  temporary  and  extraordinary  exertion,  but  it  does 
not  strengthen  the  muscles  any  more  than  does  the  whip  or  the 
spur,  that  is  applied  to  a  hard-laboring  horse  to  make  him  go  faster, 
add  to  his  strength. 

35.  Experiments  have  been  made  with  instruments  constructed  for 
the  purpose,  and  the  results  carefully  recorded,  and  these  show  that 
a  less  degree  of  muscular  power  is  possessed  by  the  same  person  when 
he  is  under  the  influence  of  alcohol  than  when  he  has  not  taken  it 
(see  foot-note  on  p.  213).     This  is  no  secret  to  men  who  go  into  train- 
ing to  bring  about  the  best  possible  development  of  their  muscular 
strength ;  men  who  intend  to  engage  in  contests,  such  as  boat-rac- 
ing, foot-racing,  and  a  great  variety  of  other  athletic  sports,  are 
taught  to  abstain  entirely  from  all  forms  of  drink  that  contain 
alcohol    if  they  would  bring  their  powers  to  the  highest  point. 

83.  The  former  use  of  grog. 

34.  Present  belief  as  to  its  use. 

35.  What  experiments  have  been  tried?     Training  of  athletes?     What  experience  of 
eoldiers? 


THE   MUSCLES.  47 

The  endurance  of  severe  and  prolonged  bodily  labor  is  not 
favored  by  the  use  of  alcohol.  The  test  recently  made  upon  the 
British  troops  during  the  war  in  the  Soudan,  showed  that  the  ex- 
hausting work,  privation  and  the  burning  heat  of  the  desert  can  be  bet- 
ter endured  by  those  who  have  not,  than  by  those  who  have  the 
ration  of  grog.  The  time  is  coming  when  this  ration  will  be  a 
thing  of  the  past,  and  that,  too,  for  good  scientific  reasons. 

36.  Abnormal  Movements  due  to  Alcohol. — The  amount 
of  disturbance  in  the  muscular  system  that  is  produced  by 
alcohol  varies  greatly  under  different  circumstances.  It  may  be 
very  great  or  very  slight  according  as  a  great  or  small  dose  of 
liquor  is  taken.  The  tongue,  the  organ  of  speech,  is  a  muscle 
that  early  betrays  the  presence  of  drink.  This  is  the  cause  of  what 
is  called  the  "  thick  "  speech  of  the  drunken  man,,  whose  words  are 
not  correctly  uttered  but  are  dropped,  cut  short  or  run  together  in 
an  unusual  and  oftentimes  unintelligible  manner.  "Seeing  double" 
is  another  muscular  disturbance  observed  in  drunkenness.  At  a 
certain  stage  of  the  drunken  fit  every  single  object  appears  to  the 
victim  to  be  double.  In  this  case  the  muscles  that  move  the  eye- 
balls are  at  fault ;  they  are  temporarily  deranged,  so  that  the  two 
eyeballs  cease  to  move  harmoniously  and  are  no  longer  brought  to 
bear  upon  the  objects  before  them,  as  in  health,  and  the  images  of 
two  objects  are  reported  to  the  brain,  while  in  reality  there  is  only 
one.  Then,  too,  objects  that  are  at  rest  appear  to  be  in  motion,  be- 
cause the  eyeballs  are  affected  by  an  unsteady,  rolling  motion.  This 
is  one  reason  why,  at  a  certain  stage,  the  drunken  man  who  tries  to 
walk  abroad,  begins  to  stagger  from  side  to  side  over  the  sidewalk, 
to  stumble  and  perhaps  to  fall,  and  sober  men  appear  to  him  to 
stagger  and  be  drunken.  The  muscles  of  his  limbs  also,  in 
their  turn,  becoming  weakened,  or  not  being  properly  controlled, 
may  refuse  to  sustain  the  forlorn  pedestrian,  and  he  may  be  seen 
clinging  for  support  to  some  friendly  lamp-post,  or,  later  on,  sink- 
ing powerless  into  the  gutter. 

36.  Does  alcohol  derange  the  muscles?  What  effect  upon  the  tongue?  The  eyes 
%nd  limbs? 


TABLE  OF  THE  PRINCIPAL  MUSCLES. 
(SEE  PLATE  9,  PAGE  30.) 


The  Head. 


Oc-cip'i-to—  fron-ta'lis.  moves  the  scalp  and  eyebrowa, 

Or-bic-u-la'ris  paTpe-brse,  closes  the  eye. 

Le-va  tor  pal  pe-bree,  opens  the  eye. 

The  Becti  muscles  (four  in  number)  move  the  eye-bail. 

™**  the  lower  Jaw- 


The  Neck. 


Sca-le'ni  muscles  move  the  neck  from  side  to  side. 

The  Trunk. 

Pec-to-ralis,  moves  the  arm  forwards. 

La-tis'si-nms  dor'si,  moves  the  arm  backwards. 

Tra-pe'za-us,  ) 

Ser-ra'tus  mag'nus,  vmove  shoulder-blade. 

Bliom-boi-de'us,       ) 

In-ter-cos'tals,  move  the  ribs  in  respiration. 

!S£Si  obbu(?uee;  }  move  the  trank  forward3- 

E-rec  tor  spi  nse,  move  the  trunk  backwards. 

The  Upper  Limb, 

Del'toid,  raises  the  arm. 

Te  res  ma'jor,  lowers  the  arm. 


i'ceps,  bends  forearm. 
Tri'ceps,  straightens  forearm. 


Flex'or  car'pi  ra-di-a'lis,       ^ 

Ex-ten'sor  car'pf  St&lis,  hmove  the  hai^ 

"     ul-na'ris,    J 
More  than  thirty  muscles  take  part  in  moving  the  fingera 

The   Lower  Limb. 
H-i'a-cus,  ^ 

llttin^sf"8'  [move  the  thigh  forward,. 
Ad-duc'tor,          J 

P^'-iSfSfei'is,  f  move  tbe  thlgb  *«*™**> 

Sar-to'ri-us  (from  Sar'tor,  a  tailor),  crosses  one  thigh  over  the  othc 

Vas'tus,'  f  move  ihe  leg  forward8- 
GrSSis  [move  the  leg  backwards, 
Tib-i-alis,  ) 

G^:?St2l'mi-uS,[™T»"'et°ot- 
So-le'us,  J 

Twenty  muscles  take  part  in  moving  the  toes. 


THE    MUSCLES. 


QUESTIONS     FOR    TOPICAL     REVIEW. 

ff. 

PAGE 

1.  What  can  you  state  of  the  number  and  division  of  the  muscles  ?  .....................  31 

2.  Describe  the  structure  of  the  muscles  .............................................  SI 

3.  Their  arrangement  in  pairs  and  consequent  action  ..................................  32 

4.  What  is  the  difference  between  the  motion  called  flexion  and  that  called  extension  ?.  .  32 

5.  Describe  their  action,  and  state  which  are  the  more  powerful  .....................  32 

6.  What  is  the  difference  between  voluntary  and  involuntary  muscles  ?  ................  32 

7.  Illustrate  the  difference  between  the  two  ...............................  ..........  32 

8.  State  all  you  can  of  the  tendons  or  sinews  .......................................  .33 

to"f'1f''i?''  i        "  "    "                          .  i  1  1  -"-"""^  34 


> 

10.  In  how  many  ancTwRat  ways  may  contraction  be  effected?  .........................    34 

11.  What  is  stated  of  after-death  contraction?.....  ...........................  .........  34 

Why  cannot  a  muscle  in  life  continue  contracted  a  long  time  ?  ......................  35 

13.  How  then  can  the  constant  beating  of  the  heart  be  explained  ?  ..............  ........  35 

14.  How  does  the  strength  of  a  man  compare  with  that  of  a  horse  ?  .....................  35 

15.  What  can  you  state  in  regard  to  the  relative  strength  of  animals  ?  .............  .  .  35,  36 

16.  What,  in  relation  to  physical  strength?  ............................................  36 

17.  What,  in  relation  to  physical  degeneracy  ?  ..........................................  36 

18.  What,  in  relation  to  the  importance  of  exercise  ?  ...............................  36,  37 

19.  What  is  the  effect  of  exercise  upon  the  heart,  skin,  and  appetite  ?  ............  .  .•  .  .  87,  3& 

20.  How  does  exercise  affect  the  current  of  the  body's  circulation  ?  ....................     37 

21.  How  does  judicious  exercise  affect  the  muscles?  ....................................  38 

22.  What  is  stated  of  violent  and  spasmodic  exercise?  .................................  38 

23.  Of  the  exercise  of  walking?  ......................................................  39 

24.  Of  running,  leaping,  and  other  modes  of  exercise  ?  ...............  .    ................  39 

25.  Of  physical  culture,  in  connection  with  out-door  exercises  ?  .......................  40 

26.  What  are  the  results  of  excessive  exercise  ?  .........................................  40 

27.  Of  the  importance  of  gymnastics  in  our  schools  and  colleges  ?  .......................  41 

28.  Of  the  importance  of  rest  from  labor  or  exercise?  ...................................  44 

29.  What  processes  take  place  during  sleep?  ...........................................  44 

30.  What  about  the  amount  of  sleep  required?  .........................................  44 

31.  What  effects  folio  win  sufficient  sleep?  .............................................  45 

32.  Illustrate  nature's  demand  for  sleep  ...............................................  45 


ITL 

THE  INTEGUMENT,  OB  SKIN. 

The  Integument — Its  Structure — The  Nails  and  Hair — The  Complexion — Tht 
Sebaceous  Glands — The  Perspiratory  Glands — Perspiration  and  its  Uses- 
Importance  of  Bathing — Different  kinds  of  Baths — Manner  of  Bathing- 
The   Benefits  of  the    Sun — Importance  of  Warm    Clothing — Poisonous 
Cosmetics. 

1.  The  Skin. — The  skin  is  the  outer  covering  of  the  body.    The 
parts  directly  beneath  it  are  very  sensitive,  and  without  its  protec- 
tion life  would  be  an  agony,  as  is  shown  whenever  by  accident  the 
skin  is  broken  or  torn  off,  the  bared  surface  being  very  tender,  and 
sensitive  even  to  exposure  to  the  air.     Nature  has  provided  the 
body  with  a  garment  that  is  soft,  pliable,  close-fitting,  and  very 
thin:  and  yet  sufficiently  strong  to  enable  us  to  come  in  contact 
witA   the  objects   that    surround   us,   without    inconvenience    or 
suffering. 

2.  The  Structure  of  the  Skin. — When  examined  under  the 
ttiicroscope,  the  skin  is  found  to  be  made  up  of  two  layers — the 
outer  and  the  inner.     The  inner  one  is  called  the  cutte,  or  true 
skin ;  the  outer  one  is  the  epidermis,  or  scarf-skin.     The  latter  is 
also  known  as  the  cuticle.     These  two  layers  are  closely  united,  but 
they  may  be  separated  from   each  other.     This  separation  takes 
place  whenever,  from  a  burn,  or  other  cause,  a  blister  is  formed;  a 
watery  fluid  is  poured  out  between  the  two  layers,  and  lifts  the 
epidermis  from  the  true  skin.    Of  the  two  layers,  the  cuticle  is  the 
thinner  in  most  parts  of  the  body,  and  has  the  appearance  of  a 
whitish  membrane.      It  is  tough  and  elastic,  is  without  feeling, 
and  does  not  bleed  whon  cut.     Examine  it  more  closely,  and  we 

1.  What  is  the  skin  ?    Parts  directly  beneath  ?    What  is  shown  ? 

2.  Microscopic  examination?    What  is  the  cutis?    The  cuticle!    Their  union?    How 
separated  ?    What  further  is  said  of  the  cuticle  ? 


THE    INTEGUMENT,    OR   SKIN.  49 

observe  that  it  is  composed  of  minute  flat  cells,  closely  compacted, 
and  arranged  layer  upon  layer. 

3.  The  outer  layer,  the  epidermis,  is  constantly  being  worn  out, 
and  falls  from  the  body  in  the  form  of  very  fine  scales.     It  is,  also, 
continually  forming  anew  on  the  surface  of  the  inner  layer.     It« 
thickness  varies  in  different  parts  of  the  body.*     Where  exposed  to 
use,  it  is  thick  and  horn-like,  as  may  be  seen  on  the  soles  of  the 
feet,  or  on  the  palms  of  the  hands  of  those  who  are  accustomed  to 
perform  much  manual  labor.     This  is  an  admirable  provision  for 
the   increased   protection  of  the   sensitive   parts   below  the   skin 
against  all  extraordinary  exposure.     Even  the  liabilities  of  these 
parts  to  injury,  are  thus  kindly  provided  for  by  "  the  Hand  that 
made  us."    (Read  Note  I.) 

4.  The  cutis,  or  true  skin,  lies  beneath  the  epidermis,  and  is  its 
origin  and  support.     It  is  firm,  elastic,  very  sensitive,  and  is  freely 
supplied  with  blood-vessels.     Hence,  a  needle  entering  it  not  only 
produces  pain,  but  draws  blood.     It  is  closely  connected  with  the 
tissues  below  it,  but  may  be  separated  by  means  of  a  sharp  instru- 

*  Like  all  other  parts  of  the  body,  the  scarf-skin  is  constantly  being  worn 
out ;  it  dries,  shrivels,  and  falls  from  the  body  in  the  form  of  fine  flakes, 
or  scales.  In  the  scalp,  these  scales  form  the  " dandruff."  As  fast  as  it  weara 
away  it  is  renewed  from  beneath.  This  seemingly  simple  process  is  very  im- 
portant, for  by  it  a  uniform  thickness  is  secured  to  the  covering  of  the  body. 
If  it  were  otherwise,  this  covering  would  grow  thicker  as  it  grew  older,  like  the 
hark  of  a  tree,  until  it  became  unwieldy;  it  would  prevent  perspiration  also, 
and  this,  as  \ve  shall  see,  would  be  fatal  to  life.  The  growth  of  the  true  skin 
is  provided  for  in  the  blood-vessels  which  abound  in  it. 

1.  The  Renewal  of  the  Cuticle. — The  skin  is  not  a  permanent  sheath, 
but  is,  as  it  were,  always  wearing  out  and  rubbing  off,  and  new  skin  is  always 
rising  up  from  underneath.  A  snake  leaves  off  his  whole  skin  at  once,  as  we 
leave  off  a  suit  of  clothes  or  a  dress,  and  sometimes  we  may  find  his  whole  cast- 
off  covering  turned  inside  out,  just  as  he  crept  out  ot  \t  In  man,  generally, 
we  do  not  notice  the  dead  particles  of  the  skin  as  it  wears  off ;  but  where 
the  cuticle  is  pretty  thick,  as  on  the  soles  of  the  feet,  we  can  see  it  peel  off  in 
little  rolls  whenever  we  wash  the  feet  in  hot  water.  After  scarlet  fever,  too, 
sometimes  the  dead  skin  comes  off  in  great  flakes,  and  from  the  hands  almost 
Hke  the  fingers  ot  a  glove. — Berners. 


3   Wearing  out  of  the  cuticle?    What  then?    Variety  in  thickness  of  cuticle?    How 
accounted  for? 

4.  Location  and  office  of  the  cutis  ?    What  further  is  said  of  it?    Papillae  ?    Touch? 

3 


50 


THE   INTEGUMENT,    OR   SKIN. 


ment.  The  surface  of  the  cutis  is  not  smooth,  but  covered  here  and 
there  with  minute  elevations,  called  papillae.  These  are  arranged 
in  rows,  or  ridges,  such  as  those  which  mark  the  palm  and  thumb  j 
their  number  is  about  80  to  the  square  line  (a  line  being  one-twelfth 
of  an  inch).  These  papillce  contain  blood-vessels  and  nerves  also, 
and  are  largely  concerned  in  the  sense  of  touch ;  hence  they  are 
abundant  where  the  touch  is  most  delicate,  as  at  the  ends  of  the 
fingers. 

5.  The    Nails   and    Hair. — These  are  modified  foims  of  the 
cuticle.     The  nail  grows  from  a  fold  of  the  cuticle  at  the  root,  and 
from  the  under  surface.     As  fast 
as  it  is  formed,  it  is  constantly 
being    pushed    outward.*     The 
rapidity  of  its  growth   can   be 
ascertained    by   filing    a    slight 
groove  on  its  surface,  and  notic- 
ing how  the   space  between  it 
and    the   root   of    the   nail 


creases,  in  the  course 


in- 
few 


of  a 

weeks.  "When  the  nail  is  re- 
moved by  any  accident,  it  will  be 
replaced  by  a  new  one,  if  the  root 
be  not  injured.  (Notes  2  and 6. ) 

6.  The  hairs  are  produced  in 
a  similar  manner ;  the  skin  form- 


Pig,  ir. 


ing  depressions,  or  hair  sacs,  from  M.THEROOTOFAHAIR  HIGHLY  MAGNIFY 

the   bottom  Of   which   they  grOW    1,  2,  3.  The  skin  forming  the  hair  sac.    4.  Se- 

baceous  glands.    5.  The  hair  sac. 
and     are     nourished     (rig.     17).    c.  TRANSVERSE  SECTION  OF  A  HAIR  HIGHLY 

They  are   found,  of  greater   or 

less  length,  on  almost  all  parts  of  the  surface,  except  the  palms  of 

the  hands  and  soles  of  the  feet.     On  certain  parts  of  the  body,  they 


*  The  practice  of  biting  the  nails  should  be  avoided  not  only  because 
of  the  ugly  shape  which  is  produced,  but  because  it  impairs  the  sense  of  touch 
in  the  ends  of  the  fingers.  In  paring  the  nails,  let  them  remain  long  enough 


5.  What  are  the  nails  and  hair?    The  growth  of  the  nail?    The  rapidity  of  its  growth? 
Accident  to  the  nail? 

6.  How  are  the  hairs  produced?    Difference  in  their  length? 


THE    INTEGUMENT,    OB   SKIN.  51 

grow  to  great  length ;  on  other  parts  they  are  so  short,  that  they  do 
not  rise  beyond  the  hair-sac  from  which  they  grow. 

7.  The  bulb,  or  root,  from  which  the  hair  arises,  is  lodged  in  a 
small  pouch,  or  depression  in  the  skin.     The  shaft  is  the  part  which 
grows  out  beyond  the  level  of  the  skin.    Its  growth  is  altogether  in 
one  direction,  in  length  alone.     The  outer  part  of  the  hair  is  quite 
firm,  while  its  interior  is  softer,  and  supplies  the  nutriment  by 
which  it  grows.     The  hair  is  more  glossy  in  health  than  at  other 
times. 

8.  The  nail  serves  as  a  protection  to  the  end  of  the  finger,  and 
also  enables  us  to  grasp  more  firmly,  and  to  pick  up  small  objects. 
The  hair,  too,  is  a  protection  to  the  parts  it  covers.     On  the  head, 
it  shields  the  brain  from  extremes  of  heat  and  cold,  and  moderates 
the  force  of  blows  upon  the  scajp.     On  the  body,  it  is  useful  in 
affording  a  more  extensive  surface  for  carrying  off  the  perspira- 
tion. 


to  nearly  cover  the  pulp  of  the  finger.  Avoid  scraping  either  surface  of  the 
nail;  do  not  injure  the  "quick." 

2.  The  Life  of  the  Cells  of  the  Body — "The  life  of  the  body 
is  long  under  fortunate  circumstances ;  that  of  our  cells  is  short.  "We  all 
know  that  the  surface  of  the  body  is  covered  by  layers  of  cells.  The  super- 
ficial layers  are  in  loose  connection  ;  they  are  cells  in  old  age.  The  friction  of 
our  clothing  daily  removes  an  immense  number  of  them.  A  cleanly  person 
who  uses  sponge  and  towel  energetically  every  day  rubs  off  a  still  greater 
quantity. 

"  "We  swallow  ;  our  tongue  acts  in  speaking  ;  drink  and  food  pass  this  way. 
Now,  the  mucous  membrane  of  the  mouth  is  covered  with  layers  of  cells. 
Here,  also,  many  thousand  senile  cells  are  rubbed  off  daily.  And  so  on 
through  the  entire  digestive  tract.  An  immense  number  of  cells — these  living 
corner-stones  of  the  body — is  thus  lost  daily. 

"  To  show  the  duration  of  life  in  one  kind  of  cell,  let  us  turn  to  the  human 
nail  The  latter,  growing  from  a  furrow  of  the  skin,  is  made  up  of  skin-cells. 
In  the  depth  of  the  furrow,  youth  prevails  ;  at  the  upper  margin — which  we 
trim — old  age.  Berthold  proved  that  a  nail-cell  lives  four  months  in  summer 
and  five  in  winter.  A  person  dying  in  his  80th  year,  has  changed  his  nail 
200  times,  at  least — and  the  nail  appeared  such  an  inanimate,  unvarying 
thing  !  No  other  cells,  we  believe,  have  a  life  nearly  so  long  as  that  of  the 
naiL  " — Compendium  of  Histology  by  Heinrich  Frey. 


7.  Root  of  the  hair?    Shaft?    Firmness  and  softness  of  the  hair? 
*.  Office  of  the  nail?    Of  the  hair?    Give  the  illustrations. 


THE   INTEGUMENT,    OR   SKIN. 


9.  Complexion. — In  the  deeper  cells  of  the  cuticle  lies  a  pig- 
ment, or  coloring-matter,  consisting  of  minute  colored  grains.     On 
this  pigment  complexion  depends;   and   its   presence,  in   less   or 
greater  amount,  occasions  the  difference  of  hue  that  exists  between 
the  light  and  the  dark  races  of  men,  and  between  the  blonde  and 
the  brunette  of  the  white  races.     Freckles  are  due  to  an  irregular 
increase  of  this  coloring  matter. 

10.  The  sun  has  a  powerful  influence  over  the  development  of 
this  pigment,  as  is  shown  by  the  swarthy  hue  of  those  of  the  white 
race  who  have  colonized  in  tropical  climates.     It  is  also  well  illus- 
trated by  the  fact,  that  among 

the  Jews  who  have  settled  in 
northern  Europe,  there  are  many 
who  are  fair-complexioned,  while 
those  residing  in  India  are  as  dark 
as  the  Hindoos  around  them. 

11.  An  Albino  is  a  person  who 
may  be  said  to   have  no   com- 


Fia.  18.— SHOWING  A  HAIR  AND  SECTION  o* 

SKIN  HIGHLY  MAGNIFIED. 


plexion;  that  is,  there  is  an  en- 
tire absence  of  coloring  matter 
from  the  skin,  hair,,  and  iris  of 
the  eye.  This  condition  exists 
from  birth,  and  more  frequently 
occurs  among  the  dark- races,  and 
in  hot  climates,  although  it  has 
been  observed  in  almost  every 
race  and  clime. 

12.  Sebaceous  Glands. — In  all  parts  of  the  surface  where  the 
liairs  grow,  are  to  be  found  the  sebaceous,  or  oil-producing  glands. 
These  glands  are  little  rounded  sacs,  usually  connected  with  the  hair- 
bulbs  ;  and  upon  these  bulbs  they  empty  their  product  of  oil,  which 
acts  as  a  natural  dressing  for  the  hair  (4,  Fig.  17).  A  portion  of 
the  sebaceous  matter  passes  out  upon  the  surface,  and  prevents  the 
cuticle  from  becoming  dry  and  hard.  The  glands  situated  upon  the 

9.  On  what  does  the  complexion  depend?    Light  and  dark  races?    Freckles? 

10.  Influence  of  the  sun?    How  illustrated ?    Jews? 

11.  What  is  an  Albino  ?    Where  are-Albinos  found  ? 

12.  What  are  sebaceous  glands  ?    How  do  they  act  1    Sebaceous  glands  of  the  face  ?    How 
do  they  act? 


THE   INTEGUMENT,   OR   SKIN.  53 

face  and  forehead  open  directly  upon  the  skin.  In  these,  the  seba- 
ceous matter  is  liable  to  collect,  and  become  too  hard  to  flow  off 
naturally. 

13.  These  glands  on  the  face  and  forehead  frequently  appear  on 
the  faces  of  the  young  as  small,  black  points,  which  are  incorrectly 
called   "worms."     It  is  true,  that  occasionally  living  animalcules 
are  found  in  this  thickened  sebaceous  matter,  but  they  can  only  be 
detected  by  the  aid  of  the  microscope.     This  sebaceous  matter  acts 
not  only  to  keep  the  skin  flexible,  and  furnish  for  the  hair  an  oily 
dressing,  but  it  especially  serves  to  protect  the  skin  and  hair  from 
the  acridity  arising  from  the  perspiration. 

14.  The  Perspiratory  Glands. — The  chief  product  of  the  skin's 
action  is  the  perspiration.     For  the  formation  of  this,  there  are  fur- 
nished countless  numbers  of  little  sweat-glands  in  the  true  skin. 
They  consist  of  fine  tubes,  with  globe-like  coils  at  their  deeper  ex- 
tremity.    Their  mouths  or  openings  may  be  seen  with  an  ordinary 
magnifying-glass,  upon  the  fine  ridges  which  mark    the    fingers. 
These  tubes,  if  uncoiled,  measure  about  one-tenth  of  an  inch  in 
length.     In  diameter  they  are  about  one  three-hundredth  of  an 
inch,  and  upon  parts  of  the  body  there  are  not  far  from  three  thou- 
sand of  these  glands  to  the  square  inch.     Their  whole  number  in 
the  body  is,  therefore,  very  great;    and  it  is  computed,  if  they 
were  all  united,  end  to  end,  their  combined  measurement  would  ex- 
ceed three  miles. 

15.  The  Sensible  and  Insensible  Perspiration. — The  pores  of 
the  skin  are  constantly  exhaling  a  watery  fluid;  but,  under  ordi- 
nary circumstances,  there  is  no  moisture  apparent  upon  the  surface, 
for  it  evaporates  as  rapidly  as  it  is  formed.     This  is  called  insen- 
sible perspiration.     Under  the  influence  of  heat  or  exercise,  however, 
this  fluid  is  formed  more  abundantly,  and  appears  on  the  surface  in 
minute,  colorless  drops.     It  is  then  termed  sensible  perspiration. 

16.  "Water  is  the  chief  component  of  this  fluid,  there  being  about 
ninety-eight  parts  of  water  to  two  parts  of  solid  matter.    The  quantity 
escaping  from  the  body  varies  greatly,  according  to  the  temperature 

13.  Black  points,  called  worms  ?    Animalcules?   Service  performed  by  sebaceous  matter? 

14.  Perspiration  ?     Sweet  glands  ?     Of  what  do  they  consist?     Dimension  of  the  tubes? 

15.  What  is  sensible  perspiration  ?    Insensible  perspiration  ? 

16.  Components  of  perspiration?     Upon  what  does  perspiration  depend?    Amount  of 
perspiration  cjulyj 


54  THE   INTEGUMENT,    OR   SKIN. 

of  the  air,  the  occupation  of  the  individual,  and  other  circum- 
stances. The  average  daily  amount  of  perspiration  in  the  adult  is 
not  far  from  two  pints,  or  more  than  nine  grains  each  minute. 

17.  The   Uses  of  the   Perspiration. — Besides  liberating  from 
the  blood  this  large  amount  of  water,  with  the  worn-out  matter 
it  contains,  the  perspiration  serves   to   regulate   the   temperature 
of  the  body.     That  is  to  say,  as  evaporation  always  diminishes 
temperature,  so  the  perspiration,  as  it  passes  off  in  the  form  of  fine 
vapor,  cools  the  surface.     Accordingly,  in  hot  weather  this  function 
is  much  more  active,  and  the  cooling  influence  increases  in  propor- 
tion.    When  the  air  is  already  charged  with  moisture,  and  does  not 
readily  receive  the  vapor  of  the  body,  the  heat  of  the  atmosphere 
apparently  increases,  and  the  discomfort  therefrom   is   relatively 
greater. 

18.  The  importance  of  perspiration  is  shown  by  the  effects  that 
often  follow  its  temporary  interruption,  namely,  headache,  fever, 
and  the  other  symptoms  that  accompany  "  taking  cold."     When 
the  perspiration  is  completely  checked,  the  consequences  are  very 
serious.     Experiments  have  been  performed  upon  certain  smaller 
animals,  as  rabbits,  to  ascertain  the  results  of  closing  the  pores  of  the 
skin.     When  they  are  covered  by  a  coating  of  varnish  impervious 
to  water  and  gases,  death  ensues  in  from  six  to  twelve  hours — the 
attendant  symptoms  resembling  those  of  suffocation.    (Read  Note  3.) 

3.  On  Taking  Cold. — "  Of  all  the  things  to  which  humanity  is  liable, 
there  is  none  which  recurs  more  frequently,  and  whose  consequences  are  more 
troublesome  and  often  dangerous,  than  *  taking  cold.'  Some  persons  have 
quite  a  faculty  for  taking  cold,  while  others  do  so  but  rarely.  And  yet  the 
One  does  not  argue  delicacy  of  constitution,  or  the  other  strength.  The  body 
Of  man  has  a  constant  and  agreeable  temperature  in  health,  the  variation  being 
slight.  In  fact,  any  great  variation  is  incompatible  with  health,  and  consti- 
tutes disease.  Clothes,  by  preventing  the  radiation  away  of  heat  from  tiie 
surface,  retain  it,  and  so  the  feeling  of  cold  is  not  so  great — that  is,  the  surface 
does  not  become  so  cold.  Clothes  are  non-conductors  of  heat  when  dry;  but 
let  them  be  saturated  with  water,  and  unless  the  loss  of  heat  be  met  by 
increased  production,  there  is  a  lowering  of  the  body  temperature — '  taking 
cold.'  Thus,  if  exertion  be  continued,  and  more  heat  is  produced  to  meet  the 


17.  What  does  perspiration  set  free  from  the  blood  ?   What  other  service  does  perspiratioc 
perform?    Explain  the  process. 

18.  Effect  of  interruption  of  excretion?    What  experiments  are  mentioned? 


THE   INTEGUMENT,    OR   SKIN.  55 

19.  It  is  related  that,  at  the  coronation  of  one  of  the  Popes,  about 
three  hundred  years  ago,  a  little  boy  was  chosen  to  act  the  part  of 
an  angel ;  and,  in  order  that  his  appearance  might  be  as  gorgeous  as 
possible,  he  was  covered  from  head  to  foot  with  a  coating  of  gold- 
foil.     He  was  soon  taken  sick,  and  although  every  known  means 
were  employed  for  his  recovery,  except  the  removal  of  his  fatal 
golden  covering,  he  died  in  a  few  hours.* 

20.  The  Importance  of  Bathing. — From  these  considerations, 
it  is  evident  that  health  must  greatly  depend  upon  keeping  the  skin 
clean.     "  He  who  keeps  the  skin  ruddy  and  soft,  shuts  many  gates 
against  disease."      For  as  the  watery  portion  of  the  perspiration 
evaporates,  the  solid  matter  is  left  behind.     There,  also,  remain  the 
scales  of  the  worn-out  cuticle,  and  the  excess  of  sebaceous  matter. 
In  order  to  secure  the  natural  action  of  the  skin,  these  impurities 
require  to  be  removed  by  the  frequent  application  of  water.    (Read 
Note  4. ) 

loss  until  a  change  of  dry  clothing  is  procurable,  no  injury  results.  But  let 
the  wet  clothes  be  worn  without  a  corresponding  heat  production,  as  when 
children  sit  down  in  school  in  their  wet  clothes,  or  the  shop-boy  stands  in  his 
moist  garments ;  then  there  is  a  rapid  loss  of  heat,  a  lowering  of  the  body 
temperature,  and  a  cold  is  'caught.'  So  is  a  cold  caught  by  wet  feet,  when 
the  heat  is  radiated  away  from  the  feet  ;  if  exercise  be  continued  the  cold  is 
not  experienced.  A  damp  bed  gives  cold  because  the  moist  bedclothes  conduct 
away  the  heat,  and  the  body  temperature  is  lowered. " — Fothergill  on  the  Main- 
tenance of  Health. 

*  A  clogged  action  of  the  skin  is  disastrous  in  many  diseases,  but 
especially  those  attended  by  an  eruption,  or  "  breaking  out."  One  of  these — 
small-pox — is  exceedingly  fatal  among  the  American  Indians,  whole  tribes  hav- 
ing been  swept  away  by  it.  And  this  is  explained  by  the  fact  that  they  habit- 
ually close  their  pores  by  covering  their  bodies  with  bears'  grease,  as  a  protec- 
tion against  the  cold,  and  with  earthy  paints  as  a  means  of  decoration. 

4.  Bathing. — "When  the  civilization  of  Egypt,  Greece,  and  Rome  faded, 
the  world  passed  through  dark  ages  of  mental  and  physical  barbarism.  For  a 
thousand  years  there  was  not  a  man  or  woman  in  Europe  that  e^er  took  a 
bath,  if  the  historian  of  those  times,  Michelet,  is  to  be  believed,  ft  o  wonder 
that  there  came  the  wondrous  epidemics  of  the  mi  idle  ages,  which  cut  off  one- 
iourth  of  the  population  of  Europe — the  spotted  plague,  the  black  death,  sweat- 
ing sickness,  and  the  terrible  mental  epidemics  which  followed  in  their  traiu— 


19.  Give  the  story  in  relation  to  the  bov  covered  with  gold  foil. 

20.  Give  the  quotation.    Perspiration  } 


56  THE    INTEGUMENT,    OR    SKIN. 

21.  In  warm  climates,  and  during  hot  weather,  hathing  is  espe- 
cially necessary.  For  a  person  in  good  health,  a  daily  cold  bath  is 
advisable.  To  this  should  be  added  occasionally  a  warm  bath,  with 
soap,  water  alone  not  being  sufficient  to  remove  impurities  of  a 
greasy  nature.  Soap  facilitates  this,  by  forming  with  such  sub- 
stances a  chemical  mixture,  which  is  taken  up  by  water,  and  by  it 
removed  from  the  body.  (Read  Note  5. ) 

the  dancing  mania,  the  mewing  mania,  and  the  biting  mania.  Not  only  their 
persons,  but  their  houses  were  uncleanly,  even  in  the  classes  that  were  well- 
to-do.  Filth,  instead  of  being  abhorred,  was  almost  sanctified. " — Lyon  Play- 
fair. 

5.  An  Imaginary  Conversation  on  Baths  and  Bathing. — "  I  have 
often  amused  myself,  by  fancying  one  question  which  an  old  Roman  emperor 
would  ask,  were  he  to  rise  from  his  grave  and  visit  the  sights  of  London  under 
the  guidance  of  some  minister  of  state.  The  august  shade  would,  doubtless, 
admire  our  railroads  and  bridges,  our  cathedrals  and  our  public  parks,  and 
much  more  of  which  we  need  not  be  ashamed.  But  after  a  while,  I  think,  he 
would  look  round,  whether  in  London,  or  in  most  of  our  great  cities,  inquir- 
ingly and  in  vain,  for  one  class  of  buildings,  which  in  his  empire  were  wont  to 
be  most  conspicuous  and  splendid.  'And  where,'  he  would  ask,  'are  your 
public  baths  ? '  And  if  the  minister  of  state  who  was  his  guide  should  answer — 
'  O  great  Caesar,  I  really  do  not  know.  I  believe  there  are  some  somewhere  in 
some  out-of-the-way  place  ;  and  I  think  there  have  been  some  meetings  lately, 
and  an  amateur  concert,  for  restoring,  by  private  subscriptions,  some  baths  and 
wash-houses  which  had  fallen  to  decay.  And  there  may  be  two  or  three  more 
about  the  metropolis  ;  for  parishes  have  power  to  establish  such  places,  if  they 
think  fit,  and  choose  to  pay  for  them  out  of  the  rates  : ' — Then,  I  think,  the 
august  shade  might  well  make  answer — '  We  used  to  call  you,  in  old  Rome, 
northern  barbarians.  It  seems  that  you  have  not  lost  all  your  barbarian 
habits.  Are  you  aware  that,  in  every  city  in  the  Roman  empire,  there  were, 
as  a  matter  of  course,  public  baths  open,  not  only  to  the  poorest  freeman,  but 
to  the  slave,  usually  for  the  payment  of  the  smallest  current  coin,  and  often 
gratuitously  ?  Are  you  aware  that  in  Rome  itself,  millionaire  after  millionaire, 
emperor  after  emperor,  built  baths,  and  yet  more  baths  ;  and  connected  with 
them  gymnasia  for  exercise,  libraries,  and  porticoes,  wherein  the  people  might 
have  shade  and  shelter,  and  rest  ?  Are  you  aware  that  these  baths  were  of 
the  most  magnificent  architecture,  decorated  with  marbles,  paintings,  sculp- 
tures, fountains,  what  not  ?  And  yet  I  had  heard,  in  Hades  down  below, 
that  you  prided  yourselves  here  on  the  study  of  the  learned  languages.  "— 
Rev.  Charles  Kingsley  on  the  Air-mothers. 


21.  Ablution  in  warm  climates  ?    What  advice  is  given  S 


THE    INTEGUMENT,    OB   SKIN.  57 

22.  There  is  a  maxim  by  the  chemist  Liebig,  to  the  effect,  that 
the  civilization  of  a  nation  is  high,  in  proportion  to  the  amount  of 
soap  that  it  consumes ;  and  that  it  is  low,  in  proportion  to  its  use  of 
perfumes.     In  some  degree,  we  may  apply  the  same  test  to  the 
refinement  of  an  individual.     The  soap  removes  impurity ;  the  per- 
fume covers,  while  retaining  it.     (Read  Notes  6  and  7. ) 

23.  The  Different  Kinds  of  Baths. — All  persons  are  not  alike 
able  to  use  the  cold  bath.     When  the  health  is  vigorous,  a  prompt 
reaction  and  glow  upon  the  surface  will  show  that  it  is  beneficial. 
Where  this  pleasurable  feeling  is  not  experienced,  but  rather  a  chill 
and  sense  of  weakness  follows,  we  are  warned  that  the  system  will 
not,  with  impunity,  endure  cold  bathing.     Most  persons  experience 
the  best  results  when  the  water  is  about  the  temperature  of  the 
body— "blood-heat." 

24.  It  should  also  be  borne  in  mind,  that  the  warm  or  hot  bath 

6.  Care  of  the  Skin  and  Nails. — Much  ignorance  prevails  amongst  the 
public  as  to  the  use  of  soap  and  water.     Those  who  have  very  sensitive  skins 
should  use  soft  water,  for  the  face  at  all  events,  and  the  best  water,  if  it  can 
be  had,  is  rain-water  with  the  cold  taken  off  it.     Nor  is  it  every  kind  of  soap 
which  is  tolerated  by  such  persons ;  probably  the  safest  soaps  are,  not  those 
which  are  said  to  contain,  but  those  which  really  do  contain,  a  large  portion 
of  glycerine. 

The  culture  of  the  nails,  which  when  perfect  constitute  so  great  a  beauty, 
is  of  much  importance  ;  but  the  tendency  is  to  injure  them  by  too  much  atten* 
tion.  The  scissors  should  never  be  used,  except  to  pare  the  free  edges  when 
they  have  become  ragged  or  too  long,  and  the  folds  of  scarf  skin  which  over- 
lap the  roots  should  not,  as  a  rule,  be  touched.  The  upper  surfaces  of  the 
nails  should  on  no  account  be  touched  with  the  knife,  as  it  is  so  often  done, 
the  nail  brush  being  amply  sufficient  to  keep  them  clean,  without  impairing 
their  smooth  and  polished  surfaces. — People's  Magazine. 

7.  On  Scents. — "They  are  the  only  resource  of  rude  and  dirty  times 
against  offensive  emanations  from  decaying  animal  and  vegetable  substances, 
from  undrained  and  untidy  dwellings,  from  unclean  clothes,  from  ill- washed 
skins,  and  from  ill-used  stomachs.     The  scented  handkerchief,  in  these  cir- 
cumstances, takes  the  place  of  the  sponge  and  the  bath  ;  the  pastile  hides  the 
want  of  ventilation  ;  the  otto  of  roses  seems  to  render  the  scavenger  unneces- 
sary ;  and  a  sprinkling  of  musk  sets  all  other  smells  and  stinks  at  defiance,"— 
Johnston. 

22.  Liebig's  maxim  ?    What  further  is  added  ? 
28.  What  is  said  about  cold  bathing? 
24.  What  is  said  about  warm  bathing? 


58  THE   INTEGUMENT,    OB   SKIN. 

cannot  be  continued  so  long,  or  repeated  so  frequently,  as  the  cold> 
on  account  of  the  enervating  effect  of  unusual  heat  so  applied  to  the 
body.  For  persons  who  are  not  in  robust  health,  one  warm  bath 
each  week  is  sufficient.  Such  persons  should  be  careful  to  avoid 
every  extreme  in  reference  to  bathing,  clothing,  and  whatever 
greatly  affects  the  action  of  the  skin. 

25.  Sea-bathing  is  even   more   invigorating  than   fresh- water 
bathing.     Those  who  cannot  endure  the  fresh  water,  are  often  bene- 
fited by  the  salt-water  baths.     This  may  be  accounted  for,  in  part, 
by  the  stimulant  action  upon  the  surface,  of  the  saline  particles  of 
the  sea-water;  but  the  exciting  scenes  and  circumstances  of  sea- 
bathing also  exert  an  important  influence.     The  open-air  exercise, 
the  rolling  surf,  the  genial  weather,  and  usually  the  cheerful  com- 
pany, add  to  its  intrinsic  benefits.     (Read  Note  8. ) 

26.  Time  and  Manner  of  Bathing. — A  person  in  sound  health 
may  take  a  bath  at  almost  any  time,  except  directly  after  a  full 
meal.      The  most  appropriate  time  is  about  three  hours  after  a 

8.  The  Proper  Use  of  Sea-bathing.— "  The  length  of  time  during 
which  a  person  should  remain  in  the  water  necessarily  varies  according  to  the 
age,  sex,  and  constitutional  strength  of  the  bather.  Due  regard  should  also 
be  had  to  the  state  of  the  weather  and  season  of  the  year. 

"  In  the  case  of  children,  five,  gradually  extended  to  ten  minutes  ;  of  women, 
ten  to  fifteen  minutes ;  and  of  men,  a  quarter  of  an  hour  or  more,  is  a  fair 
average  period.  There  are  some  people,  doubtless,  to  whom  these  periods  will 
appear  insufficient,  and  who  insist  on  remaining  so  long  in  the  water  that  their 
skin  becomes  cold  and  blue,  their  teeth  begin  to  chatter,  and  a  condition  of 
general  exhaustion  comes  on  ;  people,  in  short,  who  have  the  '  most '  for  their 
money,  like  the  countryman  who  grumbled  at  having  been  conveyed  thirty 
miles  in  about  half-an  hour  by  an  express  train,  on  the  score  that  the  length 
of  time  occupied  in  the  journey  was  not  proportionate  to  the  fare  that  he  had 
paid.  On  entering  the  water,  the  bather  should  immerse  the  whole  of  the 
body  two  or  three  times,  so  as  to  get  the  action  of  the  shock  from  the  cold 
water  distributed  over  its  entire  surface.  There  should  be  no  hesitancy,  no 
dabbling  about  with  the  feet,  but  a  good  plunge  at  once  into  the  next  wave 
that  washes  in.  Upon  coming  out  of  the  water  the  bather  should  dry  the 
body  with  good  rough  towels,  dress  quickly,  and  take  a  brisk  walk  for  a  short 
distance.  If  there  be  any  feeling  of  exhaustion  or  nervous  depression,  a  little 
food  or  drink  should  be  taken." 

25.  What  is  said  about  sea-bathing? 

2&  Wliat  is  said  as  to  the  time  and  manner  of  batninjfS 


THE   INTEGUMENT,  OR   SKIN.  59 

meal,  the  noon-hour  being  probably  the  best.  For  the  cold  bath, 
taken  rapidly,  no  time  is  better  than  immediately  after  rising. 
Those  beginning  the  use  of  cold  baths  should  first  try  them  at  70° 
Fahrenheit,  and  gradually  use  those  of  a  lower  temperature.  From 
five  to  twenty  minutes  may  be  considered  the  proper  limit  of  time 
to  remain  hi  a  bath;  but  a  sensation  of  chilliness  is  a  signal  to 
withdraw  instantly,  whether  at  home,  or  at  the  sea-side.  Two  sea- 
baths  may  be  taken  daily ;  one  of  any  other  kind  is  sufficient. 

27.  The  body  should  be  warm,  rather  than  cold,  when  stepping 
into  the  bath;  and  after  it,  the  skin  should  be  thoroughly  dried 
with  a  coarse  towel.     It  is  best  to  continue  friction  until  there  is  a 
sensation  of  warmth  or  "glow  "  throughout  the  entire  surface.    This 
reaction  is  the  test  of  the  good  effects  of  the  bath.     If  reaction  is 
still  incomplete,  a  short  walk  may  be  taken,  especially  in  the  sun- 
shine.    It  is  very  congenial,  however,  both  to  health  and  comfort, 
to  rest  for  a  short  time  directly  after  bathing,  or  to  take  some  light 
refreshment.     This  is  better  than  severe  exercise  or  a  full  meal. 

28.  Bathing  among  the  Ancients. — The  Eomans  and  other 
nations  of  antiquity  made  great  use  of  the  vapor-bath  as  a  means  of 
preserving  the  health,  but  more  particularly  as  a  luxury.     Their 
method  was  not  unlike  that  employed  in  some  parts  of  Europe  at 
the  present  day.     The  public  baths  of  Kome  and  other  cities  are 
among  the  grandest  and  most  interesting  monuments  of  ancient 
luxury  and  splendor;  and  from  their  ruins  have  been  recovered 
some  of  the  most  beautiful  works  of  art. 

29.  The  Thermae,  as  the  baths  of  Rome  were  called,  were  of 
great  extent,  built  very  substantially,  and  ornamented  at  vast  ex- 
pense.    They  were  practically  free  to  all,  the  cost  of  a  bath  having 
been  less  than  a  cent.     It  is  related  that  some  persons  bathed  seven 
times  a  day.     After  the  bath  their  bodies  were  anointed  with  per- 
fumed oil.     If  the  weather  was  fine,  they  passed  directly  from  the 
Thermae  into  the  gymnasium,  and  engaged  in  some  gentle  exercise  pre- 
vious to  taking  the  midday  meal.     Between  two  and  three  in  the 
afternoon  was  the  favorite  hour  for  this  ancient  luxury.     Swim- 
ming was  a  favorite  exercise,  and  a  knowledge  of  it  was  regarded  as 

27.  Condition  of  the  body  when  bathing?    Direction,  after  bathing? 

28.  Bathing  among  the  ancients  ?    Baths  of  Rome  ? 

29.  After  the  bath  ?    Swimming  among  the  ancients  i 


60  THE   INTEGUMEFT,    OB  SKIN. 

necessary  to  every  educated  man.  Their  common  expression,  wheu 
speaking  of  an  ignorant  person,  was,  "He  can  neither  read  noi 
swim." 

30.  The   Sun -Bath.  —  Some  also  were  accustomed  daily  to 
anoint  themselves,  and  lie  or  walk  in  apartments  arranged  for  the 
purpose,  with  naked  bodies  exposed  to  the  direct  rays  of  the  sun. 
There  is  an  interesting  allusion  to  this  practice,  in  a  letter  of  the 
younger  Pliny  to  the  historian  Tacitus,  describing  the  destruction 
of  Pompeii  by  an  eruption  of  Vesuvius.     "  My  uncle  "  (Pliny  the 
elder)  "was  at  that  time  in  command  of  the  fleet  at  Misenum. 
On  the  24th  of  August,  about  one  in  the  afternoon,  my  mother 
desired  him  to  notice  a  cloud  which  seemed  of  unusual  shape  and 
dimensions.    He  had  just  returned  from  taking  the  benefit  of  the  sun, 
and  after  a  cold  bath,  and  a  slight  repast,  had  retired  to  his  study." 
Then  follows  a  description  of  the  destruction  of  Pompeii,  and  the 
death  of  the  elder  Pliny. 

31.  We  may  judge  somewhat  of  the  benefits  of  the  sun,  by 
observing  the  unnatural  and  undeveloped  condition  of  plants  and 
animals  which  are  deprived  of  light.     Plants  become  blanched  and 
tender ;  the  fish  of  subterranean  lakes,  where  the  light  of  day  never 
enters,  are  undersized,  and  have  no  eyes ;  tadpoles  kept  in  the  dark 
do  not  develop  into  frogs ;  men  growing  up  in  mines  are  sallow, 
pale,  and  deformed.     Besides  the  well-known  effect  of  solar  light  in 
tanning  the  skin,  it  also  makes  it  thicker  and  better  able  to  resist 
exposure;   though  the  complexion  may  be   thereby   injured,  the 
health  gained  more  than  compensates  for  the  loss  of  beauty.     "  To 
make  good  the  loss  of  the  lily,  where  the  sun  has  cast  his  ray,  he 
seldom  fails  to  plant  the  rose."     (Read  Notes  9  and  10.) 

9.  Light  Influences  Growth  and  Health.— "I  have  several  times 
taken  two  potatoes  which  were  as  nearly  as  possible  alike,  and  placed  one 
under  a  bell-glass  through  which  the  light  could  pass,  and  the  other  under  a 
similar  cover  rendered  opaque,  by  several  coats  of  black  paint.  Sprouting 
went  on  unchecked  under  the  translucent  glass,  while  it  was  always  notably 
retarded  and  sometimes  prevented  in  the  potato  under  the  dark  glass.  Milne 
Edwards,  a  distinguished  French  physiologist,  performed  a  series  of  experi- 
ments which  showed  that  tadpoles  when  deprived  of  light  did  not  develop 


80.  The  sun-bath?    The  story  of  Pliny? 

81.  Benefit  of  the  sun?    Effect  upon  plants  ?    Skint 


THE   INTEGUMENT,   OB  SKIN.  61 

32.  Clothing.* — In  reference  to  clothing,  we  are  far  more  apt,  in 
our  changeful  climate,  to  use  too  little  than  too  much.  An  aphorism 
of  Boerhaave,  worth  remembering,  if  not  of  adopting,  is,  "We 
should  put  off  our  winter  clothing  on  midsummer's  day,  and  put  it  on 
again  the  day  after."  He  also  says,  "  Only  fools  and  beggars  suffer 
from  the  cold ;  the  latter  not  being  able  to  get  sufficient  clothes, 
the  others  not  having  the  sense  to  wear  them."  The  practice  of 
exposing  the  limbs  and  necks  of  young  children,  for  the  alleged 

into  the  frog.  I  have  several  times  repeated  his  experiments,  and  always  with 
confirmatory  results.  On  one  occasion  I  prevented  for  one  hundred  and 
twenty-five  days  the  development  of  a  tadpole,  by  confining  it  in  a  vessel  to 
which  the  rays  of  light  had  no  access.  On  placing  it  in  a  receptacle  open  to 
the  light,  the  process  of  transformation  was  at  once  begun,  and  was  completed 
in  fifteen  days.  The  practical  application  of  these  and  similar  observations  is 
this,  that  care  should  be  taken  both  in  health  and  disease  to  insure  a  sufficient 
amount  of  sunlight  to  the  inmates  of  houses,  and  that  it  is  impossible  to  rear 
well-formed,  strong,  and  robust  children  unless  attention  is  paid  to  this 
requirement. " — Hammond  on  the  Influence  of  Light. 

*  Man  is  the  only  animal  that  requires  clothing ;  and  as  he  advances 
from  barbarism  to  civilization,  more  and  more  attention  is  paid  to  dress  as  a 
means  of  protection  against  cold.  As  a  rule,  more  harm  arises  from  using  too 
little  clothing  than  too  mu~h,  especially  in  a  changeful  climate  like  our  own. 

10.  Light  in  the  Sick-room. — "It  is  the  unqualified  result  of  all  my 
experience  with  the  sick,  that  second  only  to  their  need  of  fresh  air  is  their 
need  of  light ;  that,  after  a  close  room,  \rhat  hurts  them  most  is  a  dark  room  ; 
and  that  it  is  not  only  light,  but  direct  sunlight  they  want.  You  had  better 
carry  your  patient  about  after  the  sun,  according  to  the  aspect  of  the  rooms, 
if  circumstances  permit,  than  let  him  linger  in  a  room  when  the  sun  is  off. 
People  think  that  the  effect  is  upon  the  spirits  only.  This  is  by  no  means  the 
case.  Who  has  not  observed  the  purifying  effect  of  light,  and  especially  of 
direct  sunlight,  upon  the  air  of  a  room  ?  Here  is  an  observation  within  every- 
body's experience.  Go  into  a  room  where  the  shutters  are  always  shut  (in  & 
sick-room  or  a  bed -room  there  should  never  be  shutters  shut),  and  though  the 
room  be  uninhabited — though  the  air  has  never  been  polluted  by  the  breath- 
ing of  human  beings,  you  will  observe  a  close,  musty  smell  of  corrupt  air — of 
air  unpurified  by  the  effect  of  the  sun's  rays.  The  mustiness  of  dark  rooms 
and  corners,  indeed,  is  proverbial.  The  cheerfulness  of  A  room — the  usefulness 
of  light  in  treating  disease — is  all-important.  It  is  a  curious  thing  to  observe 
how  almost  all  patients  lie  with  their  faces  turned  to  the  light,  exactly  as 
plants  always  make  their  way  toward  the  light." — Florence  Nightingale's  Notes 
On  Nursing. 

32.  Direction  about  clothing?    Exposing  limbs  of  children  ?    Clothing,  night  and  day? 


62  THE   INTEGUMENT,    OB   SKIS. 

purpose  of  "  hardening  "  them,  is  quite  hazardous.  It  is  not  to  "be 
denied  that  some  seem  to  be  made  tough  by  the  process.  But  it  is 
so  only  with  the  rugged  children  :  the  delicate  ones  will  invariably 
suffer  under  this  fanciful  treatment.  As  the  skin  is  constantly  act- 
ing, by  night  as  well  as  by  day,  it  is  conducive  both  to  cleanliness 
and  comfort  to  entirely  change  the  clothing  on  retiring  for  the 
night.  The  day-clothing  should  be  aired  during  the  night,  and  tho 
bedding  should  be  aired  in  the  morning,  for  the  same  reason, 
(Read  Notes  n  and  12. ) 

11.  Under-clothing  and  Bedding. — All  clothing  worn  during  the  day 
should  be  removed  at  night.     A  practice  prevails  in  tropical  countries  of  shak- 
ing  thoroughly  every  article  of  apparel  just  before  it  is  placed  on  the  body. 
The  motive  which  prompts  this  comes  from  the  fear  lest  a  centipede  or  other 
lively  and  virulent  specimen  of  natural  history  has  hid  itself  somewhere  within 
the  folds  of  the  garment.     Even  without  the  danger  of  wearing  one's  shirt  in 
conjunction  with  such  an  intruder,  it  is  an  excellent  practice  to  shake  it  and 
every  other  article  of  clothing  thoroughly  before  putting  then?  on.     The  gar- 
ments worn  next  to  the  skin  should  be  changed  before  they  become  saturated 
with  the  secretions  of  the  sebaceous  glands.     This  can  be  accomplished  by 
renewing  them  twice  a  week,  though  the  majority  of  people  only  change  them 
once  in  that  period.     Combe  recommends  to  wear  two  sets  of  flannels,  each 
being  worn  and  aired  by  turns,  on  alternate  days  ;  he  likewise  praises  a  prac- 
tice common  in  Italy,  namely,  instead  of  beds  being  made  up  in  the  morning 
the  moment  they  are  vacated,  and  while  still  saturated  with  the  nocturnal  ex- 
halations, the  bed-clothes  are  thrown  over  the  backs  of  chairs,  the  mattresses 
shaken  up,  and  the  window  thrown  open  for  the  greater  part  of  the  day.     This 
practice,  so   consonant  with  reason,  imparts  a  freshness  which  is  peculiarly 
grateful  and  conducive  to  sleep.     Florence  Nightingale,  who  never  fails  to 
speak  plainly,  says  :  "  Feverishness  is  generally  supposed  to  be  a  symptom  of 
fever ;  in  nine  cases  out  of  ten  it  is  a  symptom  of  bedding.     A  real  patient 
should  have  two  beds,  remaining  only  twelve  hours  in  each  ;  on  no  account  to 
carry  his  sheets  with  him." — Draper  (in  Part). 

12.  Rules  as  to  Clothing. — Protection  against  Cold. — For  equal  thick- 
nesses, wool  is  much  superior  to  either  cotton  or  linen,  and  should  be  worn  for 
all  under  clothing.     In  cases  of  extreme  cold,  besides  wool,  leather  or  water- 
proof clothing  is  useful.     Cotton  and  linen  are  nearly  equal. 

Protection  against  Heat. — Texture  has  nothing  to  do  with  protection  from 
the  direct  solar  rays  ;  this  depends  entirely  on  color.  White  is  the  best  color ; 
then  gray,  yellow,  pink,  blue,  black.  In  hot  countries,  therefore,  white  or 
light-gray  clothing  should  be  chosen.  In  the  shade  the  effect  of  color  is  not 
marked.  The  thickness  and  the  conducting  power  of  the  material  are  the  con- 
ditions (especially  the  former)  which  influence  heat 


THE   INTEGUMENT,    OR   SKIN.  63 

33.  Poisonous  Cosmetics. — The  extensive  use  of  cosmetics  f or 
the  complexion  is  a  fertile  source  of  disease.  The  majority  of  these 
preparations  contain  certain  poisonous  mineral  substances,  chiefly 
lead.  The  skin  rapidly  absorbs  the  fine  particles  of  lead,  and  the 
system  experiences  the  same  evil  effects  that  are  observed  among  the 
operatives  in  lead  works  and  painters,  namely,  "painters'  colic," 
and  paralysis  of  the  hands,  called  "  wrist-drop." 

34.  Certain  hair-dyes  also  contain  lead,  together  with  other 
noxious  and  filthy  ingredients.  These  do  not  work  as  great  harm 
as  the  cosmetics,  since  they  are  purposely  kept  away  from  the  skin ; 
but  they  rob  the  hair  of  its  vitality.  Eye-washes,  too,  are  made 
from  solutions  of  lead,  and  many  an  eye  has  been  ruined  by  theii- 
use.  Thej  deposit  a  white  metallic  scale  on  the  surface  of  the  eye, 
which,  when  in  front,  permanently  blurs  the  sight. 

The  body  should  not  only  be  so  protected  by  its  covering  as  to  be  kept  from 
rain  and  damp,  but  the  clothing  must  be  so  ventilated  that  the  emanations 
from  the  skin  shall  not  accumulate.  The  wearing  of  the  unventilated  beaver 
hat,  or  fur  cap,  is  a  ready  method  of  suppressing  the  natural  growth  of  the 
hair,  and  of  causing  the  retention  of  that  effete  epithelial  scale  commonly 
called  scurf,  or  dandruff.  The  wearing  ^f -tightly-fitting  water-proof  coats  can. 
not  be  habitually  practiced  without  danger^RTthe  wearer  ;  the  very  painful 
and  troublesome  ailment,  rheumatism,  has  in  many  persons  been  produced  by 
this  manner  of  locking  in  the  excretions  of  the  surface. — Dr.  B.  W* 
Richardson. 


33.  Cosmetics  ?    Painters'  colic  ? 


64  THE   INTEGUMENT,    OB   SKIN. 


QUESTIONS    FOR   TOPICAL  REVIEW. 

PAGE 

1.  What  are  the  characteristics  of  the  skin,  and  what  office  does  it  perform  ? 48 

2.  What  can  you  state  of  the  structure  of  the  skin  ? 48 

3.  Describe  the  cuticle  and  tell  its  use 49 

4.  Describe  the  cutis  or  true  skin  and  tell  its  use 49 

5.  What  can  you  state  of  the  nature  and  growth  of  the  nail  ? 50 

6.  Explain  growth  of  the  hair? - 50 

7.  Of  the  nature  and  growth  of  the  hair  ? ,. 50,  51 

8.  Of  the  offices  performed  by  the  nails  and  hair?... » A*'   f  C 51 

9.  What  is  an  Albino ? »,... .'VjAH::   ...  52 

10.  How  is  the  difference  in  complexion  in  different  persons  accounted  for  ? 52 

11.  How  is  the  presence  of  freckles  accounted  for  ?.  .3.  IrA . 52 

12.  How  does  Nature  provide  a  dressing  for  the  hair? 1 52 

13.  What  is  the  composition  of  perspiration  ? 53 

14.  What  other  service  do  the  sebaceous  glands  perform  ? v 53 

15.  State  what  you  can  of  the  perspiratory  glands  and  their  number  ? 53 

16.  What  is  the  difference  between  sensible  and  insensible  perspiration  ? 53 

17.  State  the  uses  and  importance  of  perspiration  ? 54 

18.  What  impurities  gather  naturally  on  the  skin  ? 54 

19.  What  the  effects  of  stopping  perspiratory  action  ? 54,  55 

20.  Repeat  what  is  said  of  the  importance  of  bathing? 55,  56 

21.  Different  kinds  of  baths  for  different  individuals ....  57 

22.  When  should  we  indulge  in  cold,  warm,  and  sea-bathing  ? 58 

23.  What  is  the  effect  in  each  case  ? 58 

24.  What  directions  are  given  as  to  the  time  and  manner  for  bathing? 58,  59 

25.  What  is  related  of  bathing  among  the  ancients? 59 

26.  Directions  after  the  bath  ? 59 

27.  What  is  related  to  show  the  antiquity  of  sun-bathing  ? 60 

28.  What  are  the  effects  of  sun-bathing  ? ' 60 

29.  What  directions  are  given  in  relation  to  clothing  the  body  ? 61 

30.  What  can  you  state  of  poisonous  cosmetics  ? 63 

31.  Of  hair-dyes  and  eye-washes 63 


CHAPTER    rV. 

THE  CHEMISTRY  OP  FOOD. 

The  Source  of  Food — Inorganic  Substances —  Water — Salt — Lime — Iron — Or^ 
ganic  Substances — Albumen,  Fibrin,  and  Caseine — The  Fats  or  Oils — The 
Sugars,  Starch,  and  Gum — Stimulating  Substances — Necessity  of  a  Regu- 
lated Diet. 

1.  The   Source   of  Food. — The  term  food  includes  all  those 
substances,  whether  liquid  or  solid,   which  are  necessary  for  the 
nourishment  of  the  body.     The  original  source  of  all  food  is  the 
earth,  which  the  poet  has  fitly  styled  the  "  Mother  of  all  living." 
In  her  bosom,  and  in  the  atmosphere  about  her,  are  contained  all 
the  elements  on  which  life  depends.     But  man  is  unable  to  obtain 
nourishment  directly  from  such  crude  chemical  forms  as  he  finds  in 
the  inorganic  world.  (  They  must,  with  a  few  exceptions,  be  pre- 
pared for  his  use,  by  being  transformed  into  new  and  higher  com- 
binations, more  closely  resembling  the  tissues  of  his  own  body. 

2.  This  transformation  is  effected,  first,  by  the  vegetable  world. 
But  all  plants  are  not  alike  useful  to  man,  while  some  are  absolutely 
hurtful.     Accordingly,  he  must  learn  to  discriminate  between  that 
which  is  poisonous  and  that  which  is  life-supporting.     Again,  all 
parts  of  the  same  plant  or  tree  are  not  alike  beneficial :  in  some, 
the  fruit ;  in  others,  the  leaves ;  and  in  others,  the  seeds  only  are 
sufficiently  refined  for  his  use.     These  he  must  learn  to  select ;  he 
must  also  learn  the  proper  modes  of  preparing  each  kind  for  his 
table,  whether  by  cooking  or  other  processes.     (Read  Note  i.) 

1.  The  Circle  of  Organic  Life, — Man,  as  an  animal,  is  chemically  an 
oxidizing  agent,  reducing  again  to  primitive  forms  the  principles  built  up  by 
the  vegetable  world,  and  taken  in  by  him  either  directly  as  vegetables,  or  in- 
directly in  the  shape  of  the  material  of  other  animals.  Without  vegetable  life 


1.  The  term  food  ?    Source  of  food  ?    Need  of  preparing  food  ? 

2.  Usefulness  and  hurtfulness  of  plants?    What  then  must  man  do?    Parts  of  the  same 
plant  or  tree? 


86  THE   CHEMISTRY   OP   FOOD. 

3.  Again,  certain  forms  of  the  vegetable  creation  which  are 
anfit,  in  their  crude  state,  for  man's  food,  and  which  he  rejects,  are 
chosen  as  food  by  some  of  the  lower  animals,  and  are,  by  them, 
made  ready  for  his  use.  Thus  the  bee  takes  the  clover,  that  man 
cannot  eat,  and  from  it  collects  honey.  The  cattle  eat  the  husks  of 
corn  and  the  dried  grass,  that  are  by  far  too  coarse  for  man,  and  in 
their  own  flesh  convert  them  into  tissues  closely  resembling  his 
muscular  tissue.  In  this  way,  by  the  aid  of  the  transforming  pro- 
cesses of  the  vegetable  and  animal  creations,  the  simple  chemical 
elements  of  the  mineral  kingdom  are  elaborated  into  our  choice 
articles  of  food.  (Read  Note  2. ) 

animals  could  not  exist,  and  never  could  have  existed  ;  side  by  side  they  grow 
and  flourish,  indispensable  to  each  other's  existence  ;  the  tree  breaking  up  the 
exhaled  carbonic  acid  of  the  animal — the  carbon  being  stored  up  in  its  increas- 
ing mass — while  the  oxygen  is  returned  again,  free  and  unconibined,  to  the 
atmosphere  for  the  respiratory  needs  of  the  animal  world.  Round  and  round 
go  the  elementary  bodies  in  ceaseless  change  of  form,  nevertheless  never  more 
than  they  were  at  first  and  will  be  at  the  last — the  atomic  material  of  this 
planetary  sphere  being  ever  absolutely  the  same  in  amount.  The  material  of 
the  bodies  of  Saul  and  his  sons,  when  burnt  by  the  men  of  Israel  after  their 
ignominous  exposure  at  Bethshan,  in  consequence  of  their  defeat  on  Mount 
Gilboa,  are  circulating  amongst  us  still ;  it  served  others  before  them,  and  has 
formed  part  of  thousands  since.  It  is  quite  within  the  bounds  of  chemical 
possibility  that  some  of  the  atoms  contained  in  the  fated  apple  of  Eve,  may 
have  lain  in  the  material  of  the  apple  which  revealed  to  Newton  the  law  of 
gravitation." — Fothergill  on  the  Maintenance  of  Health. 

2.  The  Food  Circle  in  Nature.—"  There  are  the  same  ultimate  elements 
in  flesh  as  in  flour,  the  same  in  animals  as  in  vegetables.  The  vegetable  draws 
food  from  the  soil  and  from  the  air.  and  being  fully  matured,  it  or  some  part 
of  it  is  eaten  by  the  animal.  But  in  completing  the  circle,  the  vegetable  re^ 
ceives  and  thrives  upon  the  animal  itself,  in  whole  or  in  part,  or  the  refuse 
which  it  daily  throws  off.  The  very  bones  of  an  animal  are  by  nature  or  man 
made  to  increase  the  growth  of  vegetables  and  really  to  enter  into  their  struc- 
ture ;  and  being  again  eaten,  animals  may  be  said  to  eat  their  own  bones,  and 
Jive  on  their  own  flesh.  Hence  there  is  not  only  an  unbroken  circle  in  the 
production  of  food  from  different  sources,  but  even  the  same  food  may  be 
shown  to  be  produced  from  itself.  Surely  this  is^an  illustration  of  the  fable  of 
the  young  Phoenix  arising  from  the  ashes  of  its  parent"— Edward  Smith  on 
Foods. 


3.  Certain  forms  of  vegetable   creation?     Example  of  the   bee?     Cattle?     The  ir 


THE   CHEMISTRY   OF   tfOOD.  6? 

4.  Inorganic  Substances. — The  substances  we  use  as  food  are 

classified  as  organic  and  inorganic.  By  organic  substances  are  meant 
those  derived  from  living  forms,  such  as  vegetables  and  animals. 
Inorganic  substances  are  those  simpler  inanimate  forms  which  be- 
long to  the  mineral  kingdom.  The  former  alone  are  commonly 
spoken  of  as  food ;  but  the  latter  enter  very  largely  into  the  consti- 
tution of  the  body,  and  must  therefore  be  present  in  our  food. 
With  the  exception  of  two  articles — water  and  common  salt — these 
substances  enter  the  system  only  when  blended  with  organic  sub 
stances. 

5.  Water. — Water,  from  a  physiological  point  of  view,  is  the 
most  important  of  all  the  articles  of  food.     It  is  everywhere  found 
in  the  body,  even  in  the  bones  and  the  teeth.     It  has  been  com- 
puted that  as  large  a  proportion  as  two-thirds  of  the  body  is  water. 
The  teeth,  the  densest  of  the  solids  in  the  human  system,  contain 
ten  per  cent,  of  water.     The  muscles,  tendons,  and  ligaments  are 
more  than  half  water ;  for  it  is  found  that  they  lose  more  than  half 
their  weight  when  dried  with  moderate  heat.     But  it  is  in  the  fluids 
of  the  body  that  water  is  found  most  abundantly.     It  gives  to  them 
the  power  of  holding  a  great  variety  of  substances  in  solution,  and 
is  the  great  highway  by  which  new  supplies  are  conveyed  to  the 
point  where  they  are  required,  and  by  which  old  particles  of  matter, 
that  have  served  their  uses,  are  brought  to  the  outlets  of  the  body 
to  be  thus  removed  from  the  system.     (Read  Notes  3  and 4.) 

3.  The  Only  Natural  Drink. — "  Water  is  the  natural  drink  of  man,  as 
it  is  of  all  organized  beings.  It  enters  more  largely  into  his  composition  than 
any  other  substance,  giving  liquidity  to  the  blood,  moisture  to  all  the  tissues," 
and  serving  as  the  great  solvent  of  the  body  ;  not  less  than  two-thirds  of  its 
weight  being  of  that  element.  It  seems  as  if  all  organic  beings  were  so  much 
"  organized  water."  "  Soft  water  is  more  wholesome  than  hard,  though  water 
moderately  hard  is  not  perceptibly  injurious.  When  very  hard,  a  part  of  the 
salts  of  lime  can  readily  be  precipitated  by  boiling.  As  a  rule,  spring  and 
well-waters,  if  brought  from  deep  fountains,  are  better  and  more  wholesome 
than  running  streams.  Well-water,  in  towns  and  cities,  unless  brought  from 
a  great  depth,  is  wholly  unfit  for  drinking  and  cooking.  The  immense  quantity 


4.  What  classification?    Define  organic  substances.     Inorganic.     Organic,  how  spoken 
of?    The  inorganic?    Water  and  salt? 

5.  Water  in  physiology?    Where  found?    Computation?    Water  in  the  teeth  ?    Muscles, 
tendons,  and  ligaments  ?    How  ascertained  ?    Water  in  the  fluids  of  the  body  ?    What  is  tha 
advantage  ? 


68  THE   CHEMISTRY  OP  FOOD. 

6.  Man  can  remain  a  longer  time  without  solid  food  than  without 
water.     He  may  be  deprived  of  the  former  for  ten  or  twelve  hours 
without  great  suffering,  but  deprivation  of  water  for  the  same  length 
of  time  will  produce  both  severe  pain  and  great  weakness.      The 
food  should  contain  not  less  than  two  parts  of  water  to  one  of  solid 
nutriment.     Water  constitutes  the  great  bulk  of  all  our  drinks,  and 
is  also  a  large  constituent  of  the  meats,  vegetables,  and  fruits  which 
come  upon  the  table.     Fruits,  especially,  contain  it  in  great  abun- 
dance, and,  in  their  proper  season,  furnish  most  agreeable  and  re- 

g  supplies  of  the  needed  fluid. 

7.  Common  Salt. — Salt,  or  sodium  chloride,  as  an  article  of  food, 
obtained  chiefly  from  the  mineral  kingdom ;  although  plants  con- 
tain it  in  small  quantities,  and  it  is  also  found  in  the  tissues  of 
nearly  all  animals  used  as  food.      In  the  human  body  it  is  an  ingre- 
dient of  all  the  solids  and  fluids.    The  importance  of  salt  to  animal 
life  in  general,  is  shown  by  the  great  appetite  for  it  manifested  by 
domestic  animals,  and  also  by  the  habitual  resort  of  herds  of  wild 
beasts  to  the  "  salt-licks  "  or  springs.     In  those  parts  of  the  world 

of  organic  matter  which  permeates  every  inch  of  the  soil,  for  many  feet  in 
depth,  precludes  the  possibility  of  water  passing  through  it  without  being 
corrupted.  River  water,  polluted  by  sewers,  is  as  disgusting  to  the  senses  as 
it  is  destructive  to  health.  The  notion  that  impure  water  can  be  rendered 
more  wholesome  by  icing  it  is  an  erroneous  one.  Ice-cold  drinks  in  summer, 
while  the  body  is  heated,  are  capable  of  producing  lifetime  disease,  and  even 
instant  death."—/.  R.  Black  on  the  Ten  Laws  of  Health. 

4.  The  Sustaining  Power  of  Water. — "  Water  is  the  most  reliable  and 
grateful  drink  for  man.  Nature  has  many  admixtures  in  the  juices  of  fruits, 
but  none  so  satisfying  to  excessive  thirst  as  pure  water.  It  will  even  prolong 
fife  when  nutritious  food  is  not  taken,  as  we  have  a  well-known  instance, 
recorded  by  Dr.  McNaughton,  in  the  transactions  of  the  Albany  Institute  of 
New  York  for  1836.  The  case  was  that  of  a  man  who  lived  upon  water  alone 
for  nfty-three^davs.  This  he  did  while  laboring  under  some  delusion  which 
impelled  him  to  abstain  from  all  ordinary  nourishment — water  alone  could  he 
be  induced  to  partake  of.  His  strength  was  tolerably  well  sustained  during 
the  first  six  weeks  ;  he  was  able,  in  fact,  to  go  out  of  doors  ;  and  even  on  the 
day  of  his  death  he  was  able  to  sit  up  in  bed."— Dr.  James  Knight. 


6.  Length  of  time  man  can  do  without  food  or  water?    Give  the  comparison?    Bulk  of 
drinks?    Constituent  of  meats,  etc. ?    Fruits? 

7.  Salt,  how  obtained  ?    Where  found  ?    In  the  human  body  2    Importance  of  salt  1  what 
else  can  you  state  of  the  value  of  salt  ? 


THE    CHEMISTRY    OP   POOD.  69 

where  salt  is  obtained  with  difficulty,  man  places  a  very  high  price 
upon  it. 

8.  Experiments  upon  domestic  animals  show  that  the  withdrawal 
of  salt  from  their  food,  not  only  makes  their  hides  rough  and  causes 
the  hair  to  fall  out,  but  also  interferes  with  the  proper  digestion  of 
food.  If  it  be  withheld  persistently,  they  become  entirely  unable  to 
appropriate  nourishment,  and  die  of  starvation.  (Read  Note  5.) 

6.  Of  Salt.— 

"  Salt-cellars  ever  should  stand  at  the  head 
Of  dishes,  wheresoe'er  a  table's  spread. 
Salt  will  all  poisons  expurgate  with  haste, 
And  to  insipid  things  impart  a  taste. 
The  richest  food  will  be  in  great  default 
Of  taste,  without  a  pinch  of  sav'ry  salt 
Yet  of  salt  meats,  the  long-protracted  use 
Will  both  our  sight  and  manhood,  too,  reduce : 
On  tables  salt  should  stand  both  first  and  last, 
Since,  in  its  absence,  there  is  no  repast. " 

— The  Code  of  the  School  of  Salernum. 

84  Animals  will  travel  long  distances  to  obtain  salt.  Men  will  barter  gold 
for  it ;  indeed,  among  the  Gallas  and  on  the  coast  of  Sierra  Leone,  brothers 
will  sell  their  sisters,  husbands  their  wives,  and  parents  their  children  for 
salt.  In  the  district  of  Accra,  on  the  gold  coast  of  Africa,  a  handful  of  salt  is 
the  most  valuable  thing  upon  earth  after  gold,  and  will  purchase  a  slave  or 
two.  Mungo  Park  tells  us  that  with  the  Mandingoes  and  Bambaras  the  use  of 
salt  is  such  a  luxury  that  to  say  of  a  man,  *  he  flavors  his  food  with  salt,'  it  is 
to  imply  that  he  is  rich  ;  and  children  will  suck  a  piece  of  rock-salt  as  if  it 
were  sugar.  No  stronger  mark  of  respect  or  affection  can  be  shown  in 
Muscovy,  than  the  sending  of  salt  from  the  tables  of  the  rich  to  their  poorer 
friends.  In  the  book  of  Leviticus  it  is  expressly  commanded  as  one  of  the 
ordinances  of  Moses,  that  every  oblation  of  meat  upon  the  altar  shall  be 
seasoned  with  salt,  without  lacking  ;  and  hence  it  is  called  the  Salt  of  the 
Covenant  of  God.  The  Greeks  and  Romans  also  used  salt  in  their  sacrificial 
cakes  ;  and  it  is  still  used  in  the  services  of  the  Latin  church — the  'parva 
mica,'  or  pinch  of  salt,  being,  in  the  ceremony  of  baptism,  put  into  the  child's 
mouth,  while  the  priest  says,  *  Receive  the  salt  of  wisdom,  and  may  it  be  a 
propitiation  to  thee  for  eternal  life.*  Everywhere,  and  almost  always,  indeed, 
it  has  been  regarded  as  emblematical  of  wisdom,  wit,  and  immortality.  To 
taste  a  man's  salt,  was  to  be  bound  by  the  rites  of  hospitality  ;  and  no  oath 
was  more  solemn  than  that  which  was  sworn  upon  bread  and  salt.  To  sprinkle 
the  meat  with  salt  was  to  drive  away  the  devil  ;  and  to  this  day,  among  th* 

8.  Experiments  upon  animals  ? 


TO  THE    CHEMISTRY   OP   FOOD. 

9.  Salt  is  usually  taken  into  the  system  in  sufficient  quantities  in 
our  food     Even  the  water  we  drink  often  has  traces  of  it.     The 
habitual  use  of  much  salt  in  cooking,  or  as  a  seasoning  at  the  table, 
is  not  wise ;  and  while  it  may  not  lead  to  consumption,  as  some 
writers  declare,  it  is  a  bad  habit  in  itself,  and  leads  to  the  desire  for 
other  and  more  injurious  condiments. 

10.  Lime. — This  is  the  mineral  substance  which  we  have  spoken  of 
before  as  entering  very  largely  into  the  composition  of  the  bones. 
It  is  the  important  element  which  gives  solidity  and  permanence  to 
the  framework    upon    which    the    body   is   built.     Calcium   tri- 
phosphate,  or  "  bone-earth,"  is  the  chief  ingredient  of  the  bones  and 
teeth,  but  is  found  in  the  cartilages  and  other  parts  of  the  body  in 
smaller  quantities.     (Read  Note  6. ) 

superstitious,  nothing  is  more  unlucky  than  to  spill  the  salt." — Letheby  on 
Food. 
6.  Phosphate  of  Lime  and  other  Inorganic  Substances.— "All 

food  contains  certain  saline  substances.  If  we  burn  a  portion  of  the  flesh  of 
any  animal,  we  may  drive  off  the  carbon,  oxygen,  hydrogen,  and  nitrogen, 
and  '  ashes '  are  left.  These  ashes  are  the  saline  and  mineral  (inorganic)  con- 
stituents of  the  animal.  They  exist  in  the  blood  and  tissues,  and  are  as 
essential  to  the  life  of  the  animal  as  those  other  elements  which  were  expelled 
by  heat.  Like  the  latter,  they  are  constantly  being  used  up  and  carried  off 
from  the  body,  and  like  them  must  be  replaced  by  means  of  our  food.  Cook- 
ing, especially  boiling,  tends  to  dissolve  away  some  of  these  salts,  and  care 
should  be  taken  to  supply  them  by  means  of  uncooked  food,  as  fresh  vegetables 
and  fruits ;  milk  also  contains  them.  One  of  the  most  important  of  these  in- 
organic substances  is  phosphate  of  lime,  or  '  bone-earth,'  as  it  is  called,  from 
the  fact  that  about  forty  per  cent,  of  healthy  bone  is  made  up  of  it.  When 
it  is  deficient,  the  bones  are  soft  and  are  liable  to  be  bent  by  the  actions  of  the 
muscles  attached  to  them,  and  a  permanent  deformity  may  be  the  consequence. 
This  form  of  lime  is  contained  in  wheat,  barley,  oats,  and  rye,  and  from  these 
sources  the  chief  supply  of  it  is  derived.  These  plants  require  phosphate  of 
lime  for  their  growth  and  the  perfecting  of  their  grains  ;  hence  it  is  supplied 
artificially  by  the  farmer.  A  diet  deficient  in  substances  yielding  the  phos- 
phate of  lime  is  injurious  to  man,  and  should  be  avoided.  Its  presence  in 
wheat-flour  accounts  in  part  for  the  fact  that  our  ordinary  loaf  of  bread  makes 
so  good  a  *  staff  of  life.'  and  that  it  is,  and  has  been,  so  widely  used  as  an 
article  of  food  by  the  strongest  and  most  vigorous  races  of  mankind. " — Lan- 
kester's  Manual. 

9.  Salt,  how  taken  into  the  system  ?    Its  use  in  cooking  ?    Consumption? 
10.  Lime  in  the  bones?    What  does  it  impart?    Chief  ingredient  of  the  bones  and  teeth? 
Where  else  found? 


THE    CHEMISTRY   OP   FOOD.  71 

11.  How  does  this  substance  find  its  way  into  the  body  ?     Meat, 
milk,  and  other  articles  obtained  from  the  animal  kingdom  contain 
it,  and  it  is  abundantly  stored  away  also  in  the  grains  from  which 
our  bread  is  made — in  wheat,  rye,  and  Indian  corn.     In  early  life, 
while  the  body  is  growing,  the  supplies  of  this  substance  should  be 
carefully  provided.     The  evil  effects  of  the  deprivation  of  it  are  too 
often  and  painfully  evident  in  the  softening  of  the  bones,  and  in  the 
predisposition  to  curvature  of  the  spine — deformities  which  are  most 
deplorable  and  which  continue  through  life. 

12.  Iron. — This  substance  is  probably  the  most  abundant  and 
widely  diffused  of  the  metals.    It  is  found  in  most  of  the  vegetables, 
and  is  a  very  important  component  of  animal  tissues.    It  enters  into 
the  composition  of  human  blood  in  about  one  part  per  thousand. 
Ordinarily,  the  food  conveys  to  the  system  enough  iron  for  its  use, 
but   it   must   sometimes   be   introduced  separately   as   a   remedy, 
especially  after  great  loss  of  blood,  or  after  some  wasting  disease. 
Under  its  influence  the  blood  seems  to  be  rapidly  restored,  and  a 
natural  color  of  the  lips  and  skin  replaces  the  pallor  caused  by 
disease. 

13.  Other  Inorganic  Substances.— In  addition  to  the  substances 
"mentioned,  the  mineral  kingdom  supplies  compounds  of  soda,  potash, 
and  magnesia,  which  are  essential  for  the  use  of  the  body.      They 
occur  in  small  quantities  in  the  body,  and  enter  it  in  combination 
with  the  various  articles  of  diet. 

14.  Organic  Substances. — These  substances  are  derived  from  the 
vegetable  and  animal  creations.     They  comprise  all  those  articles 
which  are  commonly  spoken  of  as  "  food,"  and  which  are  essential 
to  sustain  the  body  in  life  and  strength.     They  are  divided  into 
three  groups,  namely :   the  Albuminoid  substances,  the  Fats,  and 
Sugars. 

15.  The  Albuminoids. — This  class  includes  three  important  nutri- 
tive substances — (1)  Albumen,  which  gives  it  its  name ;  (2)  Fibrin,, 

. — 

11.  How  does  lime  find  its  way  into  the  tody?    Early  life  ?    Effect  of  its  deprivation? 

12.  Iron,  its  abundance  and  diffusion?  Where  found?  What  part  of  the  blood  is  it?  How 
Supplied  to  the  system  ?    In  case  of  loss  of  blood  or  wasting  disease  ? 

13.  Soda,  potash,  and  magnesia?    How  do  they  occur? 

14.  Organic  substances,  whence  derived  ?    What  do  they  comprise  ?    Groups  ? 

15.  The  Albuminoid  class,  includes  what?  These  compounds  constitute  what?   The  food? 
Their  importance ?  Their  properties? 


72  THE    CHEMISTRY   OP   POOD. 

including  gluten;  and  (3)  Caseine.  These  compounds  constitute  a 
large  part  of  the  human  body,  and  the  food  contains  them  in  propor- 
tionally large  quantities.  Their  importance  is  so  great,  and  the 
system  so  promptly  suffers  from  their  absence,  that  they  have  been 
styled  the  "nutritious  substances."  The  properties  which  they 
hold  in  common  are,  that  they  do  not  crystallize,  and  have  a  jelly, 
like  form,  except  when  heat  is  applied  to  them,  when  they  harden, 
or  coagulate. 

16.  They  likewise  decompose,  or  putrefy,  under  the  influence  of 
warmth  and  moisture.     Hence  the  decay  of  all  dead  animal  tissues. 
Cold  arrests  this  process.     It  is  well  known  that  milk,  eggs,  and  the 
like,    "  keep  "  much  longer  in  winter  than  at  other  seasons.     The 
bodies  of  elephants,  caught  in  the  ice  many  hundred  years  ago,  are 
occasionally   borne    by    the    icebergs    to    the    coast   of    Siberia, 
completely   frozen,  but   preserved  almost   perfectly   in  form  and 
limb. 

17.  Albumen  exists  in  milk,  meat,  the  grains,  and  the  j-uices  of 
many  plants ;  but  the  purest  form  is  obtained  from  the  white  of  egg. 
When  we  consider  that  an  egg  is  composed  chiefly  of  albumen  and 
water — namely,  six  parts  in  seven  ;    and  when  we  also  consider  the 
numerous,  diverse,  and  complex  tissues — the  muscles,  bones,  internal 
organs,  bill,  claws,  and  feathers — with  which  the  chick  is  equipped 
on   leaving  his  shell,  we   are   impressed   with  the  importance  of 
these    apparently    simple    constituents    of    the    food  and  body. 
(Read  Note  7.) 

7.  Weight  and  Health — "The  weight  of  the  body  is  very  generally 
assumed  to  be  an  infallible  index  or  proof  of  the  maintenance  of  a  healthy  con- 
dition of  the  body;  and  that  food  which  keeps  up  the  weight  has  been 
regarded  as  satisfactory  and  nutritious.  But  this  is  not  always  a  safe 
judgment,  owing  to  the  property  in  water  from  innutritious  food  to  make  good 
the  loss  of  weight  caused  by  the  withdrawal  of  albumen  and  fat.  The  weight 
may  remain  the  same,  while  we  are  "losing  flesh."  Fat,  also,  may  increase 
in  badly  nourished  people,  while  the  more  essential  element  of  albumen  is 
diminishing ;  the  fact  being  that  the  badly  fed  are  not  always  lighter  than 
those  who  are  well  nourished.  And  further,  the  feeling  of  satisfaction  after 
eating  is  deceptive  ;  the  Irish  peasant  who  consumes  ten  pounds  of  potatoes  in 


16.  Decomposition  ?    Effect  of  cold  ?    Illustrations  ?    Elephants  ? 

17.  In  what  substances  does  albumen  exist?    What  further  is  said  of  the  egg? 


THE   CHEMISTRY   OF   FOOD.  73 

18.  Fibrin  is  derived  from  meats,  and  exists  in  the  blood  both  of 
man  and  the  lower  animals.      Gluten,  or  vegetable  fibrin,  resembles 
closely  true  fibrin,  and  is  abundantly  furnished  in  wheat  and  other 
grains  from  which  flour  is  commonly  made.     Animal  fibrin  coagu- 
lates spontaneously  when  it  is  removed  from  the  body,  and  thus 
causes  the  "  clotting  "  of  the  blood. 

19.  Caseine  is  the  curdy  ingredient  of  the  milk,  and  a  highly  im- 
portant food-substance.      Its  coagulation  in  milk  takes  place  not 
from  heat,  but  by  the  addition  of  an  acid,  and  also  when  milk  be- 
comes sour  from   exposure  to  the  air.     It  is  commonly  effected, 
however,  by  introducing  a  piece  of  rennet,  a  preparation  made  from 
a  calf's  stomach.     The  curds,  or  caseine,  may  then  be  separated  from 
the  whey,  and  made  into  cheese,  by  pressing  it  sufficiently  to  drive 
off  the  water. 

20.  The  Fats  OP  Oils. — This  is  the  second  group  of  organic 
foods.     Those  which  are  more  solid  are  called  fats ;  the  more  fluid 
ones  are  the  oils.     Oleaginous  substances  are  supplied  in  both  ani- 
mal and  vegetable  food ;  but,  from  whatever  source  derived,  they 
are  chemically  much  alike.     They  are  insoluble  in  water,  and  yet 
they  unite  readily  with  the  watery  fluids  of  the  body,  and  are  by 
them  conveyed  to  its  various  parts  for  their  nourishment.     This  is 
due  to  their  property  of  "  emulsifying ;"  that  is,  they  are  held  in 
suspension,  in  a  finely  divided  state,  in  water.     Ordinary  milk  is 
an  example  of  an  emulsion.     We  know  that  it  contains  fat,  for 
butter  is  obtained  from  it ;  and,  under  the  microscope,  the  minute 
oil-globules  may  be  distinctly  seen. 

21.  In  our  country  and  climate,  and  also  in  colder  climates,  fatty 
articles  of  food  are  principally  derived  from  the  animal  creation, 
such  as  meat  or  flesh,  milk  and  butter.     But  most  of  the  bread- 
stuffs  contain  more  or  less  fat  or  oil — Indian  meal  as  much  as  nine 
parts  in  a  hundred. 

a  day  feels  quite  satisfied,  but  is  in  reality  badly  nourished  by  his  diet  contain- 
ing three-fourths  water.  "—Prof.  Voit,  of  Munich. 

18.  Fibrin,  gluten,  clotting  of  the  blood  ? 

19.  Caseine  ?    Its  coagulation  ?    Effect  of  rennet  ?    Making  of  cheese  ? 

20,  What  are  the  fats?    The  oils?    How  supplied?    How  alike?    EmulaifyinK?    Exam- 
plet    How  do  we  know  it? 

21,  Whence  are  fatty  articles  of  food  derived? 


74  THE   CHEMISTRY   OP   FOOD, 

22.  Among  persons  living  in  cold  climates,  the  appetite  for 
oleaginous  food  is  especially  eager ;  and  they  require  large  quanti- 
ties of  it  to  enable  them  to  resist  the  depressing  influences  of  cold. 
Since~  vegetation  is  scanty  and  immtritious,  and  the  waters  of  the 
frozen  regions  abound  in  animal  life,  they  must  rely  wholly  upon 
a  diet  derived  from  the  latter  source.  The  Esquimau  consumes 
daily  from  ten  to  fifteen  pounds  of  meat  or  blubber,  a  large  propor- 
tion of  which  is  fat.  The  Laplander  will  drink  train-oil,  and 
regards  tallow-candles  as  a  great  delicacy.  In  hot  clima  /es,  on  the 
contrary,  where  flourish  the  olive  and  the  palm,  this  kind  of  food 
may  be  obtained  from  vegetable  sources  in  abundant  quantities. 
(Read  Notes  8  and  g. ) 

8.  The  Necessity  of  Fat  in  the  Food  of  Children. — "  Children  who 
dislike  fat  cause  much  anxiety  to  parents,  for  they  are  almost  always  thin, 
and,  if  not  diseased,  are  not  healthy.     If  care  be  not  taken,  they  fall  into  a 
scrofulous  condition,  in  which  diseased  joints,  enlarged  glands,  sore  eyes,  and 
even  consumption  occur ;  and  every  effort  should  be  made  to  overcome  this 
dislike.     If  attention  be  given  to  this  matter  of  diet,  there  need  be  no  anxiety 
about  the  possibility  of  increasing  the  quantity  of  food  consumed  ;  whilst  the 
neglect,  the  dislike,  will  probably  increase  until  disease   is  produced.     The 
chief  period  of  growth — viz.,  from  seven  to  sixteen  years  of  age — is  the  most 
important  in  this  respect,  for  a  store  of  fat  in  the  body  is  then  essential. 
Those  who  are  inclined  to  be  fat  usually  like  fat  in  food,  and  then  it  may  be 
desirable  to  limit  its  use.     Some  who  cannot  eat  it  when  hot  like  it  when  cold, 
and  all  should  select  that  kind  which  they  prefer.     Those  living  in  Russia  and 
Lapland  devour  very  large  quantities — as  seven  pounds  daily — and  eat  it  even 
raw,  while  those  dwelling  in  hot  countries  use  very  little.     It  produces  more 
heat  than  any  other  kind  of  food. " — Edward  Smith  on  Health. 

9.  The  Eflfect  of  Climate  on  the  Appetite.—"  Climate  has  an  impor- 
tant influence  on  the  quantity  of  food  demanded  by  the  system  ;  and  every  one 
has  experienced  in  his  own  person  a  considerable  difference  at  different  seasons 
of  the  year.     Travelers'  accounts  of  the  amount  of  food  consumed  by  the  na- 
tives of  the  frigid  zone  are  almost  incredible.     They  speak  of  men  eating  a 
hundred  pounds  of  meat  in  a  day  ;  and  a  Russian  admiral,  Saritcheff,  men- 
tions an  instance  of  a  man  who,  in  his  presence,  ate  at  a  single  meal  a  mess  of 
boiled  rice  and  butter  weighing  twenty-eight  pounds.     Although  it  is  difficult 
to  regard  these  statements  with  entire  confidence,  the  general  opinion  is  un- 
doubtedly well  founded  that  the  appetite  is  greater  in  cold  than  in  warm 
climates.     Dr.  Hayes,  the  Arctic  explorer,  states,  from  his  own  observation, 


22.  Appetite  of  persona  in  cold  climates?    What  do  they  require?    Upon  what  must 
they  rely?    Why?    The  Esquimau?    Laplander?    Olive  and  palm? 


/X  /^JLT^l  !L    THE  CHEMISTRY  OF  FOOD.  75 

23.  The  Sugars,  br  the  Saccharine  Substances. — These  con- 
stitute the  third  and  last  group  of  the  organic  substances  which  are 
employed  as  food.     This  group  embraces,  in  addition  to  the  different 
kinds  of  Sugar,  the  varieties  of  starch  and  gum,  from  whatever 
source  derived.     The  two  substances  last  named  do  not,  at  first 
Bight,  present  many  points  of  similarity  to  sugar;  but  they  closely 
resemble  it  in  respect  to  their  ultimate  chemical  composition,  being 
made  up  of  the  same  elements,  in  nearly  the   same  proportions. 
And  their  office  in  the  system  is  the  same,  since  they  are  all  changed 
into  sugar  by  the  processes  of  digestion. 

24.  Sugar  is  chiefly  of  vegetable  origin,  the  animal  varieties 
being  obtained  from  honey  and  milk.     The  most  noticeable  charac- 
teristic of  this  substance  is  its  agreeable,  sweet  taste,  which  makes 
it  everywhere  a  favorite  article  of  food.     But  this  quality  of  sweet- 
ness is  not  possessed  by  all  the  varieties  of  sugar  in  the  same  de- 
gree; that  obtained  from  milk,  for  instance,  has  a  comparatively 
feeble  taste,  but  rather  imparts  a  gritty  feeling  to  the  tongue.     The 
other  important  properties  of  sugar  are,  its  power  to  crystallize  when 
evaporated  from  watery  solutions,  such  as  the  juices  of  many  plants ; 
a  tendency  to  ferment,  by  which  process  alcohol  is  produced;  and  a 
ready  solubility  in  water.     This  latter  quality  renders  it  very  easy 
of  digestion,  and  more  so  than  any  other  of  the  saccharine  group. 
It  is  computed  that  the  annual  production  of  sugar,  in  all  parts  of 
the  world,  is  more  than  one  million  of  tons.     The  kind  of  sugar 
that  is  in  ordinary  use,  in  this  country,  is  prepared  from  the  juice 
of  the  sugar-cane,  which  contains  eighteen  per  cent,  of  sugar.     In 
France  it  is  manufactured  from  the  beet-root,  which  holds  about 

that  the  daily  ration  of  the  Esquimaux  is  from  twelve  to  fifteen  pounds  of 
meat,  about  one-third  of  which  is  fat.  He  once  saw  an  Esquimau  consume 
ten  pounds  of  walrus  flesh  and  blubber  at  a  single  meal,  which  however  lasted 
several  hours,  with  the  thermometer  60°  or  70°  below  zero.  Some  members 
of  his  own  party  manifested  a  constant  craving  for  fatty  substances,  and  were 
in  the  habit  of  drinking  the  contents  of  the  oil-kettle  with  evident  relish." — 
Flint's  Physiology. 

23.  Which  are  the  third  of  the  organic  groups?    What  do  they  embrace  ?    Points  of  re- 
semblance ? 

24.  Origin  of  the  sugars ?    Ordinary  sugar?     Beet-root?    Maple-sugar?    Grape-sugar! 
Cane-sugar? 


76 


THE  CHEMISTRY  OF  FOOD, 


nine  per  cent. ;  the  maple-tree  of  our  climate  yields  a  similar  sugar. 
The  sweet  taste  of  fruits  is  due  to  the  presence  of  grape-sugar :  the 
white  grains  seen  on  raisins  belong  to  this  variety.  Cane-sugar  is 
more  soluble  than  the  latter,  and  has  twice  the  sweetening  power. 
(Read  Note  10.) 

25.  Starch. — This  is  the  most  widely  distributed  of  the  vegetable 
principles.  It  is  tasteless,  inodorous,  and  does  not  crystallize.  It 
consists  of  minute  rounded  granules,  which,  under  the  microscope, 
reveal  a  somewhat  uniform  structure  (Fig.  19).  Starch  will  not 

dissolve  in  cold  water,  but  in 
boiling  water  the  small  grains 
burst  open,  and  may  then  be 
dissolved  and  digested. 

26.  The  breadstuff's — wheat, 
corn,  and  rye  flours — are  more 
than  one -half  starch.  Eice, 
which  is  the  "  staff  of  life  "  to 
one-third  of  the  human  family, 
contains  eighty  per  cent.  Un- 
ripe fi'uits  have  much  starch  in 
them,  which  renders  them  in- 
digestible when  eaten  uncooked, 
for  the  grains  of  raw  starch  are 


Fio.  19.— GRANULES  OF  POTATO  STAKCH  MAG- 
NIFIED. 


10.  Why  too  much  Sugar  is  Injurious. — "  Sugar  is  very  wholesome, 
and,  as  I  told  you,  we  want  some  in  our  diet.  But  children  will  often  eat  too 
much  sugar,  just  as  they  will  eat  too  little  fat.  The  harm  it  does  them  is — 
first,  it  is  very  apt  to  spoil  the  teeth  ;  second,  it  takes  away  the  appetite  for 
other  food.  If  you  are  always  eating  sweet  cakes  and  sugar-plums,  you  will 
not  care  for  plain,  nourishing  diet.  Now,  what  is  best  for  us  all  is,  to  have 
good  appetites  for  wholesome  food ;  it  will  do  more  to  keep  us  in  health  all  our 
lives  than  anything  else ;  and  there  is  a  great  deal  in  getting  the  right  habit." 
Candies  are  frequently  adulterated  with  plaster-of-paris,  chalk,  and  certain 
forms  of  earth,  that  are  indigestible ;  but  worse  than  that,  the  coloring  mat- 
ters and  flavoring  extracts  that  are  used  in  the  bright-tinted  and  fruity- 
flavored  confectionery  are  absolute  poisons  in  many  instances,  such  as  arsenic, 
copper,  zinc,  lead,  prussic  and  sulphuric  acid. — Eerner's  Lessons  on  Health  (in 
part)-  . 

25.  Starch,  how  widely  distributed  ?    Its  qualities?    Its  constituents?    Its  solubility? 

26.  Eow  much  starch  in  bread-stuffs  ?    In  rice  ?    Unripe  fruits  ?    Eipe  fruits  ? 


THE   CHEMISTRY   OF   FOOD.  77 

but  slightly  acted  upon  within  the  body.  But,  under  the  potent 
chemistry  of  the  sun's  ray,  this  crude  material  is  converted  into 
sugar.  Thus  are  the  fruits  prepared  by  the  careful  hand  of  Na- 
ture, so  that  when  ripe  they  may  be  freely  used  without  further 
preparation. 

27.  Gum  is  commonly  found  in  those  articles  which  also  contain 
starch,  and  has  the  same  chemical  composition  as  the  latter,  but  is 
much  less  nutritious.     In  the  East,  gum-arabic   and  similar  sub- 
stances are  largely  employed  as  food.     Persons  who  travel  by  cara- 
van across  vast,  sandy  desertSj  find  such  substances  well  adapted  to 
their  wants,  since  they  are  not  perishable,  and  are  easily  packed  and 
carried. 

28.  Stimulating  Substances.— The  three  classes  of  food-princi- 
ples already  considered — the  Albuminoids,  the  Fats,  and  the  Sugars 
— comprise  all  the  more  important  organic  ingredients  of  our  food. 
There  are,  besides,  a  great  variety  of  coloring  and  flavoring  matters  J 
that  stimulate  or  increase  the  appetite  for  food  by  appealing  to  the 
eye  and  taste ;  but  they  are  not  nutritious,  and  are  quickly  sepa- 
rated from  the  truly  useful  substances,  and  do  not  long  remain  in 
the  body.     Among  these  may  be  classed  spices,  flavors  of  fruits, 
tea,  coffee,  and  vegetable  acids. 

29.  Necessity  of  a  Regulated  Diet. — A  great  variety  of  ex- 
periments have  been  tried,  in  order  to  test  the  relative  value  of  the 
different  nutritive  principles.     They  have  been  practiced  to  some 
extent  upon  man,  but  chiefly  upon  those  inferior  animals  which  re- 
quire a  similar  diet  to  man. 

30.  By  this  means  it  has  been  demonstrated  that — first,  xwhen 
any  one  of  these  substances  is  eaten  exclusively,  the  body  is  imper- 
fectly nourished,  and  life  is  shortened.     Dogs  fed  exclusively  upon 
either  albumen,  fat,  or  sugar,  soon  die  of  starvation.  /  Second,  a 
diet  long  deprived  of  either  of  these  principles  is  a  fertile  cause  of 
disease ;  for  example,  on  ship-board,  where  fresh  vegetables  are  not 
dealt  out  for  a  long  period,  scurvy  becomes  prevalent  among  the 

27.  Gum,  where  found?    Its  composition ?    Gum  Arabic? 

28.  The  three  classes  of  food  principles  ?    What  besides  ?    What  Is  said  of  them  ?    Name 
the  articles  not  nutritious. 

29.  What  is  said  of  experiments  that  have  been  tried? 

80.  What  has  been  demonstrated  in  the  first  place?    Example?    Second  demonstration? 
Example?   Give  the  illustration  in  relation  to  convertibility. 


78  THE   CHEMISTRY   OP   POOD. 

sailors.  They  are,  however,  to  a  certain  extent  mutually  converti- 
ble, and  thus  the  missing  article  is  indirectly  supplied.  For  in- 
stance, sugar  changes  to  fat  in  the  body ;  and  hence,  as  is  well 
known,  the  "hands"  on  a  sugar  plantation  grow  fat  during  the 
sugar  season,  by  partaking  freely  of  the  ripened  juices  of  the  cane. 
(Read  Note  n.) 

31.  That  is  the  best  diet,  therefore,  which  contains  some  of  each 
of  these  principles,  in  due  proportion ;  and  that  is  the  worst  which 
excludes  the  most  of  them.  The  cravings  and  experience  of  man 
had  unerringly  guided  him  to  a  correct  regulation  of  his  diet,  long 
before  the  chemistry  of  food  was  understood  ;  so  that  his  ordinary 
meals  long  ago  combined  these  various  principles,  the  necessity  and 
value  of  which  are  now  explained.  (Read  Notes  12  and  13. ) 


11.  The  Effects  of  a  Poor  Diet — "The  food  of  the  poor  in  olden 
times  was  poor  and  scanty  ;  so  much  so,  in  fact,  that  their  powers  of  life  were 
depressed  ;  and  we  believe  this  fact  had  much  to  do  with  the  fearful  mortality 
of  the  plague  throughout  Europe  during  the  middle  ages.     The  lower  classes, 
especially  those  living  in  crowded  cities,  and  subsisting  on  the  scanty  and 
monotonous  diet  that  the  historians  of  the  period  describe,  were  the  principal 
sufferers.     From  1296  to  1666,  hundreds  of  thousands  were  carried  off  by  the 
most  fearful  pestilences  the  earth  has  ever  known.     Rye  in  France  and  oats  in 
England  were  for  generations  the  almost  exclusive  diet ;  wheat  was  a  luxury, 
which  even  the  rich  might  only  indulge  in  at  Christmas.     Oats  were  known 
in  Germany  2,000  years  ago,  and  were  probably  the  original  bread -grain  for  all 
Europe." — Dr.  J.  Knight. 

12.  Variety  in  Diet  and  in  its  Preparation  Beneficial.— "Every 
dietary  should  contain  fresh  vegetables.     It  is  further  necessary  that  certain 
articles  belonging  to  the  same  class  be  varied  from  day  to  day,  otherwise  the 
appetite  cloys.     Beef  should  alternate  with  mutton,  for  example  ;  or  variety 
should  be  secured  by  different  modes  of  cooking  the  same  article.     Indeed,  it  is 
not  too  much  to  say  that  the  art  of  cookery  is  a  matter  of  national  importance, 
not  only  because  it  renders  food  palatable,  but  because  the  more  it  is  studied 
and  practiced,  the  greater  is  the  economy  which  may  be  effected.     It  is  chiefly 
in  this  relation,  that  beverages,  condiments,  etc.,  become  such  valuable  dietetic 
adjuncts." — Wilson's  Hand-book  of  Hygiene. 

13.  Some  Experiments  as  to  Pood. — "Magendie  made  numerous  ex- 
periments on  the  inferior  animals  to  test  the  value  of  different  forms  of  nutri- 
ment    He  showed  that  a  diet  exclusively  composed  of  starch  and  sugar  would 
not  support  life.     So,  too,  dogs  confined  to  white  bread  and  water  died  with 
all  the  symptoms  of  starvation  ;  but  on  the  military  brown-bread  animals  lived 


THE    CHEMISTRY    OF   FOOD. 


79 


pretty  well,  as  this  article  contains  a  greater  variety  of  the  alimentary  princi- 
ples. Other  experiments  have  given  an  account  of  geese  limited  to  some  one 
substance.  All  of  them  died — the  animal  fed  upon  gum,  on  the  sixteenth  day ; 
that  fed  with  sugar,  on  the  twenty-first  day ;  one  fed  with  starch,  on  the 
twenty-fourth  day  ;  and  one  fed  with  white  of  egg,  on  the  twenty-sixth  day. 
In  1769,  before  these  experiments  were  performed,  Dr.  Stark,  a  young  English 
physiologist,  fell  a  victim  at  an  early  age  to  ill-judged  experiments  on  himself 
as  to  the  effects  of  different  foods.  He  lived  for  forty-four  days  on  bread  and 
water,  for  twenty-nine  days  on  bread,  sugar,  and  water,  and  for  twenty-four 
days  on  bread,  water,  and  olive  oil ;  until  finally,  his  constitution  became 
broken,  and  he  died  from  the  effects  of  his  experiments." — Flint's  Physiology. 


THE    CHEMISTRY    OF    FOOD. 


QUESTIONS   FOR    TOPICAL    REVIEW. 

PAGE 

1.  What  Is  understood  by  the  term  food? 65 

2.  What  can  you  state  in  relation  to  the  source  of  food? 65 

3.  What  discriminations  and  selections  are  necessary  ? '.  ^TT.T. ...  65,  66 

4.  How  can  you  tell  the  organic  from  the  inorganic  substances  ? 67 

5.  What  relative  position  does  water  hold  as  an  article  of  food? *...» 67 

6.  In  what  parts  of  the  body  is  water  found  ? 67 

7    In  what  articles  that  we  eat  is  it  found? 68 

a   If  you  were  required  to  go  without  water  or  solid  food  for  a  number  of  days,  which 

would  you  prefer  to  have,  and  why  ? , 68 

9.  What  can  you  state  of  the  importance  of  salt  as  an  article  of  food  ? 68 

10.  How  abundant  is  salt,  and  how  does  it  find  its  way  into  the  human  system  ? 68 

11.  What  can  you  state  of  the  importance  of  lime  hi  the  body  ?    In  what  does  it  occur  ?..  70 

12.  What,  of  the  importancejjfJcQii?... ...^^ 71 

13.  WhaT  further  is  stated  ofother  inorganic  substances  ?....... TT^T nT....  i. •','."  Tl 

14.  What  in  relation  to  organic  substances  ? 71 

15.  What  can  you  state  in  relation  to  the  albuminoids? 71,72 

16.  What,  in  relation  to  albumen  ? 72 

17.  What,  in  relation  to  caseine  ? , 73 

18.  In  relation  to  the  fats  or  oils,  and  how  generally  consumed  ? 73 

19.  What  do  we  understand  by  the  sugars  or  saccharine  substances  ? 73,  74 

20.  State  what  you  can  of  sugar — its  origin  and  various  qualities 75 

21.  Of  starch — its  varieties  and  qualities 76 

22.  Of  the  abundance  of  starch,  and  its  importance  as  a  food  principle 76 

23.  What  is  stated  in  relation  to  stimulating  substances  ?. 77 

24.  Of  the  necessity  for  regulation  in  diet? 77 

25.  What  is  considered  the  most  healthful  diet 2. 78 


FOOD  AND  DRINK. 

tfeces&ity  for  Food — Waste  and  Repair — Hunger  and  Thirst — Amount  oj 
Food— Renovation  of  the  Body — Mixed  Diet — Milk— Eggs — Meat — Cooking 
—  Vegetable  Food — Bread — The  Potato — Fruits — Purity  of  Water — Action 
of  Water  upon  Lead — Coffee,  Tea,  and  Chocolate — Effects  of  Alcohol. 

1.  Necessity   fop   Food. — Activity  is  everywhere  followed  by 
vaste.     The  engine  uses  up  coal  and  water  to  produce  motion,  the 
stream  wears  away  its  bank,  the  growing  corn-blade  draws  tribute 
from   the  soil.     When  the  human  body  acts,  and  it  is  always  in 
action  during  life,  some  of  its  particles  are  worn  out  and  thrown  off. 
This  waste  must  constantly  be  repaired,  or  the  body  suffers.     In  this 
fact  is  seen  the  necessity  for  food.     The  particles,  thus  worn  out, 
being  henceforth  useless,  are  removed  from  the  body.     Our  food 
and  drink  are  rapidly  transformed  into  a  new  supply  of   living, 
useful  material,  to  be  in  turn  used  up  and  replaced  by  a  fresher 
supply. 

2.  Waste  and  Repair. — In  this  way  the  healthful  body,  though 
always  wasting,  is  always  building  up,  and  does  not  greatly  change 
in  size,  form,  or  weight.     At  two  periods  of  life  the  processes^of 
waste  and  repair  are  not  exactly  balanced.     In  early  life  the  process 
of  building  up  is  more  active,  and   in  consequence  the  form  is 
plump  and  the  stature  increases.     Repair  now  exceeds  waste,     On 
the  other  hand,  when  old  age  comes  on,  the  wasting  process  is  more 
active,  the  flesh  and  weight  dimmish,  the  skin  falls  in  wrinkles,  and 
the  senses  become  dull.     Only  during  the  prime  of  life — from  about 

1.  What  follows  activity?    Examples?.  Necessity  for  food  ? 

2.  Give  the  theory  in  relation  to  waste 'tod  repair. 


82  FOOD   AND   DRINK. 

twenty  to  sixty  years  of  age — is  the  balance  exact  between  loss 
and  gain.     (Read  Note  i. ) 

3.  Hunger  and  Thirst. — When  the  system  is  deprived  of  its 
supply  of  solid  food  during  a  longer  time  than  usual,  nature  gives 
warning  by  the  sensation  of  hunger,  to  repair  the  losses  that  have 
taken   place.      This  sensation   or  pain  appears  to   be   located  in 
the  stomach,  but  it  is  really  a  distress  of  the  system  at  large.      Let 
a  sufficient  quantity  of  nourishment  be  introduced  into  the  system 
in  any  other  way  than  by  the  mouth,  and  it  will  appease  hunger 
just  as  certainly  as  when  taken  in  the  usual  manner. 

4.  The  feeling  of  thirst,  in  like  manner,  is  evidence  that  the 
system  is  suffering  from  the  want  of  water.     The  apparent  seat  ot 
the  distress  of  thirst  is  in  the  throat ;  but  the  injection  of  water  into 
the  blood-vessels  is  found  to  quench  thirst,  and  by  the  immersion  of 
the  body  in  water,  the  skin  will  absorb  sufficient  to  satisfy  the  de- 
mands of  the  system.     The  length  of  time  that  man  can  exist 
without  food  or  drink  is  estimated  to  be  about  seven  days.    If  watet 
alone  be  supplied,  life  will  last  much  longer — there  being  cases 

1.  The  Waste  of  the  Body.—"  In  the  physical  life  of  man  there  is 
scarcely  such  a  thing  as  rest — the  numberless  organs  and  tissues  which  com- 
pose his  frame  are  undergoing  perpetual  change,  and  in  the  exercise  of  the 
function  of  each  some  part  of  it  is  destroyed.  Thus,  we  cannot  think,  feel  or 
move  without  wasting  some  proportion,  great  or  small,  according  to  the  energy 
of  the  act,  of  the  apparatuses  concerned — such  as  brain,  nerve  or  muscles. 
Now  this  waste-product  cannot  remain  in  its  original  situation,  where  it  would 
not  only  be  useless  dross,  but  also  obstructive  and  injurious.  Such  old 
material  is  being  daily  removed  from  our  bodies  to  the  average  amount  of  three 
or  more  pounds  ;  and  that  an  equal  quantity  of  new  shall  take  its  place  is  the 
first  principle  of  alimentation.  To  express  it  in  commercial  language,  the  in- 
come must  be  equal  to  the  expenditure  ;  and  in  each  of  us  the  amount  of  this 
exchange  must  in  a  lifetime  reach  many  tons.  This  tissue-change  is  so  com- 
plete, that  not  a  particle  of  our  present  body  will  be  ours  a  short  time  hence  ; 
and  we  will  be,  as  I  have  lately  seen  it  phrased,  like  the  knife  which,  after 
having  had  several  new  blades,  and  at  least  one  new  handle,  was  still  the  same 
old  knife  to  its  owner.  We  are,  in  fact,  constantly  '  moulting. ' " — Mapother'b 
Lectures  on  Public  Health. 


8.  System  deprived  of  food?    Warning?    What  is  the  pain  ?    How  proved? 
4.  Feeling  of  thirst  i    Seat  of  the  pain  ?    How  proved?   Time  a  person  can  exist  without 
food? 


FOOD   AND   DRINK.  83 

recorded  where   men  have  lived  twenty  days  and  over  without 
taking  any  solid  food.     (Read  Note  2.) 

5.  Quantity  of  Food. — The   quantity   of  food  required  varies 
greatly,  according  to  the  individual  and  his  mode  of  life.     The 
young,  and  others  who  lead  active  lives,  or  who  live  in  the  open  air, 
require  more  food  than   the  old,  the  inactive,  or  the  sedentary. 
Those  who  live  in  cold  regions  require  more  than  the  inhabitants  of 
hot  climates.      Habit,  also,  has  much  to  do  with  the  quantity  of 
food  required.     Some  habitually   eat  and  drink  more  than  they 
actually  need,  while  a  few  eat  less  than  they  should. 

6.  The  average  daily  quantity  of  food  and  drink  for  a  healthy 
man  of  active  habits  is  estimated  at  six  pounds.     This  amount  may 
be  divided  in  about  the  following  proportions :  the  mineral  kingdom 
furnishes  three  and  one-half  pounds,  including  water  and  salt ;  the 
vegetable  kingdom,   one   and  one-half   pounds,   including  bread, 
vegetables,  and  fruits  ;  the  animal  kingdom,  one  pound,  comprising 
meat,   eggs,  butter,  and   the  like.      This  quantity  is  about  one 
twenty-fourth  the  weight  of  the  body,  as  it  is  generally  computed  ; 
the  average  weight  of  an  adult  man  being  placed  at  140  pounds.    A 

2.  Hunger  and  Thirst — "  We  none  of  us  object  to  a  sharp-set  appetite  ; 
that  is  by  no  means  unpleasant,  especially  when  there  is  food  at  hand  ;  but  if 
this  is  not  the  case,  it  soon  becomes  a  craving  passion — a  strong  impelling 
power.  The  cravings  of  hunger  have  done  much  for  this  world  ;  '  look  where 
we  may,  we  see  it  as  the  motive  power  which  sets  the  vast  array  of  human 
machinery  in  action.'  Hunger  is  also  the  incentive  which  directs  our  atten- 
tion to  the  system's  need  for  food,  and  if  it  be  sharp  enough  the  most 
loathsome  substances  are  greedily  devoured.  By  it  has  man,  and  civilized 
man,  too,  been  driven  to  feed  upon  the  putrid  corpse  of  his  comrade.  Hunger 
is  one  of  the  great  forces  in  action  in  the  preservation  of  the  life  of  the  indi- 
vidual ;  and  the  fear  of  it  is  one  of  the  strongest  incentives  to  action.  But  the 
pangs  of  hunger  are  tolerable  in  comparison  with  the  tortures  of  raging  thirst. 
In  fact,  so  terrible  are  the  latter  that  they  form  one  of  the  cruelest  tortures 
which  man  can  inflict  on  man  ;  so  cruel  a  torture,  indeed,  that  it  has  rarely 
been  used,  except  in  cases  of  bitter  personal  animosity,  by  others  than  brutal 
Eastern  tyrants,  or  bigots  under  the  influence  of  religious  fanaticism." — 
Fothergill  on  the  Maintenance  of  Health. 


5.  Amount  of  food  required  ?  The  young  and  others?  Those  living  in  hot  and  cold  climates! 
Habits? 

6.  Quantity  of  food  daily  ?  How  divided  ?  Compare  with  the  weight  of  the  body. 


04  POOD    AND    DRINK. 

man,  therefore,  consumes  an  amount  of  solid  and  liquid  nutriment 
every  twenty-four  days  equal  in  weight  to  that  of  his  body,  a  cor- 
responding amount  being  excreted,  or  removed  from  the  system  in 
the  same  time.  (Read  Notes  3  and  4.) 

3.  A  Lifetime  Allowance  of  Food.— "M.  Soyer,  in  his  'Modern 
Housewife/  makes  a  calculation  as  to  how  much  food  an  epicure  of  70  j^earsof 
age  has  consumed.  This  imaginary  epicure,  who  is  supposed  to  be  a  wealthy 
personage,  is  placed  by  him  on  Primrose  Hill  at  ten  years  old  and  told  to  look 
around  him  at  the  vast  assemblage  of  animals  and  other  objects  he  will  in  the 
^ourse  of  a  lifetime  send  down  his  throat — the  sight  of  which  is,  of  course,  de- 
scribed as  appalling.  Among  the  other  things,  he  is  to  devour  30  oxen,  200 
sheep,  100  calves,  200  lambs,  50  pigs,  1,200  fowls,  300  turkeys,  263  pigeons, 
120  turbot,  140  salmon,  30,000  oysters,  5,745  Ibs.  of  vegetables,  243f  Ibs.  of 
butter,  24,000  eggs,  and  4^  tons  of  bread,  besides  fruits,  sweetmeats,  etc., 
and  49  hogsheads  of  wine,  548  gals,  of  spirits,  and  about  3,000  gals,  of  tea  and 
coffee.  This  is  a  mere  outline  of  what  we  are  told  is  destined  to  be  consumed. 
To  show  there  is  no  exaggeration,  Soyer  assures  us  that  he  has  from  experience 
made  up  a  scale  of  food  for  the  day  for  a  period  of  60  years,  and  it  amounts  to 
33|  tons  of  meat,  farinaceous  food,  and  vegetables,  etc."  —  Journal  of 


4.  A  Daily  Ration  for  an  Adult  Man. — "  We  may  arrive  at  something 
like  an  average  daily  diet  by  taking  the  case  of  the  man  in  good  health, 
weighing  154  Ibs.,  and  measuring  5  feet  8  inches  in  height.  Simply  to  main- 
tain hi&  body,  without  loss  or  gain  in  weight,  his  ration  of  food  should  not 
contain  less,  during  24  hours,  than  the  following  proportions  and  quantities  of 
the  main  ingredients : 

THE  AVERAGE  DAILY  DIET  FOR  AN  ADULT. 


FOOD  SUBSTANCES. 

PER  CENTUM. 

WEIGHT. 

81.5 

Ibs.       oz. 
5          8 

grs 
320 

Albuminoids  or  flesh  formers    .  .  ........... 

8.0 

4 

110 

10.6 

11 

178 

Fat  

8.0 

3 

337 

Common  salt   ..  .  . 

.7 

825 

Phosphates,  potash,  salts,  etc...,  ....     . 

.8 

170 

100. 

6         13 

128 

"Water,  it  will  be  remembered,  enters  into  the  composition  of  every  article 
of  food  as  well  as  in  the  liquids  we  drink.      In  reality,  the  weight  of  the  dry 


POOD   AND   DRINK.  00 

7.  Renovation  of  the  Body. — By  this  process,  so  far  as  weight  i« 
concerned,  the  body  might  be  renewed  every  twenty-four  days  j  but 
these  pounds  of  food  are  not  all  real  nutriment.     A  considerable 
portion  of  that  which  we  eat  is  innutritious,  and  though  useful  in 
various  ways,  is  not  destined  to  repair  the  losses  of  the  system.   An 
opinion  has  prevailed  that  the  body  is  renewed  throughout  once  in 
seven  years ;  how  correct  this  may  be,  it  is  not  easy  to  decide,  but 
probably  the  renovation  of  the  body  takes  place  in  a  much  shorter 
period.      Some  parts  are  very  frequently   renewed,  the  nutritive 
fluids  changing  more  or  less  completely  several  times  during  the 
day.     The  muscles,  and  other  parts  in  frequent  exercise,  change 
often  during  a  year ;  the  bones  not  so  often,  and  the  enamel  of  the 
teeth   probably   never    changes  after   being    once   fully    formed. 
(Read  Note  5. ) 

8.  Mixed  Diet. — The  habits  of  different  nations  in  respect  to  diet 
exhibit  the  widest  and  strangest  diversity.    The  civilized  cook  their 
food,  while  savages  often  eat  it  in  a  raw  state.    Some  prefer  it  when 
fresh;  others  allow  it  to  remain  until  it  has  become  tainted  with 
decay.      Those  dwelling  in  the  far  north  subsist  almost  wholly  on 

food  we  take  will  exceed  that  given  above  ;  chiefly  for  the  reason  that  they  do 
not  come  to  us  pure  and  unmixed  with  fibrous  material  and  gelatine,  whose 
use  in  nourishing  the  body  is  limited  and  uncertain." — Kensington  Museum 
Hand-Book  on  Food. 

5.  The  Renewal  of  the  Body. — "To  meet  these  constant  chemical 
changes,  material  is  taken  in,  in  the  form  of  food  and  drink,  which  is  being 
constantly  assimilated,  and  so  nutrition  and  repair  are  conducted.  The  rapid- 
ity with  which  these  changes  are  carried  on  is  much  greater  than  is  usually 
supposed.  Paley,  in  his  'Natural  Theology,'  states  that  seven  years  are 
requisite  for  the  perfect  renewal  of  the  body  ;  and  this  statement,  owing  partly 
to  the  mysticism  associated  with  the  number  7,  is  generally  accepted  and 
believed.  The  time  really  is  rather  months  than  years  ;  but  it  is  absurd  to  fix 
a  time  which  must  necessarily  vary  in  different  individuals,  being  much  less  in 
the  infant  than  in  the  aged,  in  the  active  than  the  indolent ;  widely  different, 
too,  in  various  tissues,  from  the  epithelium  lining  of  the  glands  of  the  stomach, 
renewed  several  times  in  each  act  of  digestion,  to  the  enamel  of  the  tooth, 
•which  is  probably  never  renewed  during  a  lifetime." 


7.  How  often,  then,  might  the  body  be  renewed  ?  Why  is  itnotT  Opinion?  How  correct? 
What  further  is  stated? 

8.  Habits  of  nations?  Give  the  different  cases. 


86  POOD   AND    DRINK. 

animal  food,  while  those  living  in  hot  climates  have  bountiful 
supplies  of  delicious  fruits  with  which  to  satisfy  all  their  bodily 
wants.  One  race  subsists  upon  the  banana,  another  upon  the 
blubber  of  seals.  In  temperate  climates,  a  diet  composed  partly 
of  vegetable  and  partly  of  animaj  food  is  preferred.  {Read  Note  6. ) 

9.  The  important  point  to  consider  is,  however,  not  one  of  origin, 
but  whether  the  chemical  principles  (mentioned  in  the  last  chapter) 
enter  into  the  composition  of  fiie  diet.     A  purely  vegetable  diet  may 
be  selected  which  would   contain  all  the  principles  necessary  to 
sustain  life.    It  is  recorded  of  Louis  Cornaro,  a  Venetian  noble,  that 
he  supported  himself  comfortably  for  fifty-eight  years  on  a  daily 
allowance  of  twelve  ounces  of  vegetable  food,  and  about  a  pint  of  light 
wine.    On  the  other  hand,  the  food  of  John  the  Baptist,  consisting  of 
"  locusts  and  wild  honey,"  is  an  example  of  the  sustaining  power  of 
a  diet  chiefly  animal  in  its  origin. 

10.  In  our  climate,  those  who  lead  active  lives  crave  an  allowance 
of  animal  food  ;   and  it  has  been  found  by  experience  that  with  it 
they  can  accomplish  more  work  and  are  less  subject  to  fatigue,  than 
without  it.      Among  nations  where  an  exclusively  vegetable  diet 
is   employed,    indigestion    is    a    disorder    especially     prevalent. 
(Read  Note  7.) 

6.  Different  Effects  of  Animal  and  Vegetable  Food. — "Raw  meat 
gives  fierceness  to  animals,  and  would  do  the  same  to  man.      This  is  so  true 
that  the  English,  who  eat  their  meat  underdone,  seem  to  partake  of  this  fierce- 
ness more  or  less,  as  shown  in  pride,  hatred,  and  contempt  of  other  nations. " — 
De  La  Mettrie. 

"  The  carnivora  are,  in  general,  stronger,  bolder,  and  more  pugnacious  than 
the  herbivora  on  which  they  prey  ;  in  like  manner,  those  nations  who  live  on 
vegetable  food  differ  in  disposition  from  such  as  live  on  flesh.'* — Liebig. 

7.  A  Mixed  Diet  affords  the  best  Results — "  The  mixed  diet  to 
which  the  injlination  of  man  in  temperate  climates  seems  usually  to  lead  him, 
when  circumstances  allow  that  inclination  to  develop  itself  freely,  appears  to 
be  fully  conformable  to  the  construction  of  his  dental  and  digestive  apparatus, 
as  well  as  to  his  instinctive  cravings.     And  whilst  on  the  one  hand  it  may  be 
freely  conceded  to  the  advocates  of   'vegetarianism,'  that  a  well-selected 
vegetable  diet  is  capable  of  producing,  in  the  greatest  number  of  individuals, 
the  highest  physical  development  of  which  they  are  capable,  it  may,  on  ths 

C.  The  point  to  consider?   Vegetable  diet  ?    Louis  Comoro  t  John  the  Baptist? 
10.  What  has  been  found  in  our  climate?   Exclusive  vegetable  diet? 


FOOD   AND    DRINK.  87 

11.  The  necessity  for  occasionally  changing  or  varying  the  diet,  is 
seen  in  the  fact  that  no  single  article  comprises  all  the  necessary 
principles  of  food,  and  that  the  continuous  use  of  any  one  diet, 
whether  salt  or  fresh,  is  followed  by  defective  nutrition  and  disease. 
There  is  one  exception  to  this  rule  :    in  infancy,  milk  •  alone  is  best 
calculated  to  support  life ;  for  then  the  digestive  powers  are  incom- 
pletely developed,  and  the  food  must  be  presented  in  the  simplest 
form  possible.      It  should  also  be  remembered  that  too  rich  diet  is 
injurious,  just  as  truly  as  one  that  is  inadequate.    When  the  food  of 
horses  is  too  nutritious,  instinct  leads  them  to  gnaw  the  wood-work 
of  their  mangers. 

12.  Different  Articles  of  Diet— Milk.— Milk  is  the  earliest 
nutriment  of  the  human  race,  and  in  the  selection  and  arrangement 
of  its  constituents,  may  be  regarded  as  a  model  food,  no  other  single 
article  being  capable  of  sustaining  life  so  long.      Cows'  milk  holds 
caseine,  one  of  the  albuminoids,  about  five  parts  in  one  hundred ; 
a  fatty  principle,  when  separated,  known  as  butter,  about  four  parts  ; 
sugar  of  milk  four  parts  ;  water  and  salts  eighty-seven  parts.      The 
caseine  and  fatty  substance  are  far  more  digestible  in  milk  than 
after  they  have  been  separated  from  it  in  the  form  of  cheese  and 
butter. 

13.  Since  milk,  in  itself,  is  so  rich  an  article  of  food,  the  use  of  it 
as  a  beverage  is  unwise,  unless  the  quantity  of  the  other  articles 
consumed  be  reduced  at  the  same  time.      The  milk  sold  in  cities  is 
apt  to  be  diluted  with  water.      The  way  to  detect  the  cheat  is  by 
testing  the  specific  gravity  of  the  article.    Good  milk  is  about  1030 ; 

other  hand,  be  affirmed  with  equal  certainty,  that  the  substitution  of  a 
moderate  proportion  of  animal  flesh  is  in  no  way  injurious  ;  but,  so  far  as  OUT 
evidence  at  present  extends,  this  seems  rather  to  favor  the  highest  mental  de- 
velopment. And  we  can  scarcely  avoid  the  conclusion  that  the  Creator,  by 
conferring  on  a  man  a  remarkable  range  of  choice,  intended  to  qualify  him  for 
subsisting  on  those  articles  of  diet,  whether  animal  or  vegetable,  which  he 
finds  most  suitable  to  his  tastes  and  wants." — W.  B.  Carpenter  on  the  Print 
dples  of  Physiology. 

11.  Necessity  for  change  in  diet?  Continuous  use  of  the  same  diet?  Exception?  Why  I 
Too  rich  diet  ?   Horses  ? 

12.  Milk  as  a  model  food  ?   Cows'  milk  ?  The  constituents  when  separated  ? 
18.  Milk  as  a  beverage  ?  Milk  sold  in  cities  2  How  to  detect  the  cheat? 


90  FOOD    AND    DRINK. 

softens  it  throughout.  When  soup  is  to  be  made  an  opposite 
course  should  be  pursued;  for  then  the  object  is  to  extract  the 
juices  and  reject  the  fibre.  Meat,  for  such  purpose,  should  be  cut 
in  small  pieces  and  put  into  cold  water,  which  should  then  be  gradu- 
ally raised  to  boiling  heat.  (Read  Note  9. ) 

20.  Roasting  is  probably  the  best  method  of  cooking  meat, 
especially  "joints"  or  large  pieces,  as  by  this  process  the  meat  is 
cooked  in  its  own  juices.  Roasting  should  begin  with  intense  heat, 
and  be  continued  at  a  moderate  temperature,  in  order  to  prevent 
the  drying  out  of  the  nutritious  juices,  as  by  this  process  an  outer 
coating  or  crust  of  coagulated  albumen  is  formed.  During  this 
process  the  meat  loses  one-fourth  of  its  weight,  but  the  loss  is 
almost  wholly  water,  evaporated  by  the  heat.  Too  intense  or  pro- 
longed heat  will  dry  the  meat,  or  burn  it.  Frying  is  the  worst 

9.  Cooking  Paves  the  Way  for  Easy  Digestion — The  objects  to 
be  obtained  by  cooking  meat  are :  1.  To  coagulate  the  albumen  and  blood  of 
the  tissues,  so  as  to  render  the  meat  agreeable  to  the  sight.  2.  To  develop 
flavors,  and  to  make  the  tissue  crisp,  as  well  as  tender,  and  therefore  more 
easy  of  mastication  and  digestion.  3.  To  secure  a  certain  temperature,  and 
thus  to  be  a  means  of  conveying  warmth  to  the  system.  4.  To  kill  parasites 
in  the  tissues  of  the  meat 

The  action  of  heat  should  not  be  continued  after  these  objects  are  accom- 
plished, as  the  meat  will  thereby  be  rendered  indigestible.  If  a  piece  of  meat 
be  placed  in  water  which  is  briskly  boiling,  a  crust,  so  to  speak,  is  formed  by 
the  rapid  coagulation  of  the  albumen  upon  and  near  the  surface ;  so  that  the 
juice  of  the  meat  cannot  escape,  nor  the  water  penetrate  its  interior.  If,  on 
the  other  hand,  the  meat  be  put  in  cold  water,  and  slowly'heated,  the  albumen 
is  gradually  dissolved,  and  exudes  into  the  water,  making  good  soup,  but  leav- 
ing the  meat  poor  and  tasteless.  Even  in  roasting  meat  the  heat  must  be 
strongest  at  first,  and  it  may  then  be  much  reduced.  The  juice  which,  as  in 
boiling,  flows  out,  evaporates,  in  careful  roasting,  from  the  surface  of  the 
meat,  and  gives  to  it  the  dark  brown  color,  the  lustre,  and  the  strong  aromatic 
taste  of  roast  meat.  All  baked  and  roasted  fatty  foods  are  apt  to  disagree  with 
delicate  stomachs ;  and  it  is  often  remarked  that,  although  bread  and  butter^ 
boiled  puddings,  boiled  fish,  or  boiled  poultry  can  be  eaten  freely  without  dis- 
comfort, yet  toast  and  butter,  or  meat  pies  and  pastry,  or  fried  fish,  or  roasted 
fowl  will  disagree  with  the  stomach. — Letheby  on  Food. 


20.  Roasting?    How  should  it  be  3one?    Give  the  philosophy  of  the  process.     Frying]? 


POOD   AND    DRINK.  91 

possible  method,  as  the  heated  fat,  by  penetrating  the  meat,  or 
other  article  placed  in  it,  dries  and  hardens  it,  and  thus  renders 
it  indigestible. 

21.  Trichina. — It  should  be   remembered  that  ham,  sausages, 
and  other  forms  of  pork,  should  never  be  eaten  in  a  raw  or  imper- 
fectly cooked  condition.     The  muscle  of  the  pig  is  often  infested 
by  a  minute  animal  parasite,  or  worm,   called    trichina   spiralis. 
This  worm  may  be  introduced  alive,  in  pork  food,  into  the  human 
body,  where  it  multiplies  with  great  rapidity,  and  gives  rise  to  a 
painful  and  serious  disease.     This  disease  has  been  prevalent  in 
Germany,  and  cases  of  it  occur  from  time  to  time  in  this  country. 

22.  Fish. — The  part  of  fish  that  is  eaten  is  the  muscle,  just  as 
in  the  case  of  the  meats  and  poultry.     It  closely  resembles  flesh  in 
its  composition,  but  is  more  watery.     Some  varieties  are  very  easy 
of  digestion,  such  as  salmon,  trout,  and  cod;  others  are  quite  indi- 
gestible, especially  lobsters,  clams,  and  shell-fish  generally.     A  diet 
in  which  fish  enters  as  the  chief  article,  is  ill  adapted  to  strengthen 
mind  or  body,  while  its  continued  use  is  said  to  be  the  fertile 
source  of  nearly  every  form  of  disease  of  the  skin.     Some  persons 
are   so   constituted   that  they  can   eat  no  kind  of  fish  without 
experiencing  unpleasant  results. 

23.  Vegetable  Food.  — The  list  of  vegetable  articles  of  diet  is  a 
very  long  one,  including  the  grains  from  which  our  breadstuffs  are 
made,  the  vegetables  from  the  garden,  and  the  fruits.     All  the 
products  of  the  vegetable  kingdom  are  not  alike  useful.     Some  are 
positively  hurtful;  indeed  the  most  virulent  poisons,  as  strychnia 
and  prussic  acid,  are  obtained  from  certain  vegetables.     Again,  of 
euch  articles  as  have  been  found  good  for  food,  some  are  more 
nourishing  than  others;  some  require  very  little  preparation  for 
use,  while  others  are  hard  and  indigestible,  and  can  only  be  used 
after  undergoing  many  preparatory  processes.      Great   care  must 
therefore  be  exercised,  and  many  experiments  made,  before  we  can 
arrive  at  a  complete  knowledge  in  reference  to  these  articles  of  diet. 

21.  What  is  "  Trichina?"    How  guarded  against? 

22.  What  part  of  fish  is  eaten?    What  does  it  resemble?    Fish  as  food  for  digestion f 
Fish  as  a  diet? 

23.  List  of  vegetable   articles?    Usefulness   of  the   different  vegetables?    Strychnia! 
What  further  is  said  in  relation  to  the  nourishing  and  other  qualities  of  vegetables  ? 


92  FOOD     AND     DRINK, 

Tea,  coffee,  and  other  substances  from  which  drinks  are  made  are  of 
vegetable  origin. 

24.  Bread. — Wheat  is  the  principal  and  most  valuable  kind  of 
grain  for  the  service  of  man.     Bread  made  from  wheat-flour  has 
been  in  use  for  many  hundreds  of  years,  and  on  this  account,  aa 
well  as  because  of  its  highly  nourishing  properties,  has  been  aptly 
called  "the  staff  of  life."     We  never  become  tired  of  good  bread  aa 
an  article  of  daily  food.     The  white  kinds  of  flour  contain  more 
starch  and  less  gluten  than  the  darker,  and  are  therefore  less  nutri- 
tious.    The  hard-grain  wheat  yields  the  best  flour.     In  grinding 
wheat,  the  chaff  or  bran  is  separated  by  a  process  called  "bolting." 
Unbolted   flour  is   used    for  making    brown   or    Graham   bread. 
(Read  Note  10. ) 

25.  The  form  of  bread  most  easily  digested  is  that  which  has 
been  "  leavened,"  or  rendered  porous  by  the  use  of  yeast,  or  by  some 

10.  Bread. — "The  health  and  power  of  a  nation,  as  of  an  army,  depend 
greatly  on  its  food.  The  quality  of  bread  in  any  nation,  community,  or  family 
is  a  pretty  good  measure  of  its  civilization.  No  one  can  entirely  dispense  with 
it  Good  or  bad,  in  some  form  it  must  be  had.  So  it  is,  and  has  been  from 
the  earliest  records  of  the  race,  and  so  it  will  doubtless  continue.  Leavened 
or  fermented  bread  is  as  old  as  the  time  of  Moses,  and  its  value  has  been  fully 
tested.  Whatever  be  the  precise  action  of  the  leaven,  it  transforms  the  grain 
by  partial  decomposition  of  its  original  elements,  and  leaves  as  its  resultant 
what  all  men  in  all  ages  have  approved.  Is  the  art  of  making  good,  honest, 
leavened,  Bible  bread  lost  in  Massachusetts,  as  some  of  our  friends  declare  ? 
Baker's  bread  is  almost  universally  adulterated.  Bread  hastily  made  in  fam- 
ilies is  mixed  in  a  variety  of  ways,  with  a  variety  of  chemicals,  and  is  gener- 
ally imperfectly  cooked.  Very  often  the  elements  of  wheat  and  fat  which  the 
body  demands  (a  wise  and  witty  clergyman  of  the  last  generation  used  to  say, 
*  bread  is  the  staff  of  life,  but  bread  and  butter  is  a  gold-headed  cane ')  are 
furnished  in  underdone  pastry,  made  from  flour  and  hog's  lard.  Any 
family  who  will  take  the  pains  can  have  good  bread.  It  involves  not  more 
than  ordinary  skill  and  judgment.  It  is  to  be  found  on  the  continent  of 
Europe,  on  all  the  great  lines  of  travel,  and  is  as  common  among  the  people  of 
France  and  Germany  as  it  is  rare  with  us.  The  materials  for  an  honest, 
wholesome  loaf  are  simple  and  not  expensive.  The  value  of  time  and  labor 
required  for  kneading  the  dough  are  the  only  difficulties,  and  these  we  would 
not  undervalue  ;  they  are  in  many  families  very  serious,  and  not  easily  over- 
come."— Derby  on  the  Food  of  Massachusetts. 

24.  Wheat?    "Staff  of  life?    White  flour?     Hard-grain  wheats*    Bolting?    Graham 
bread? 

26.  Laavened  bread?    Unleavened?    Hot  bread? 


FOOD    AND    DRINK.  93 

similar  method.  Unleavened  bread  requires  much  more  mastica- 
tion. Hot  bread  is  unwholesome,  because  it  is  not  firm  enough  to 
be  thoroughly  masticated,  but  is  converted  into  a  pasty,  heavy  mass, 
that  is  not  easily  digested. 

26.  Wheaten  bread  contains  nearly  every  principle  requisite  for 
sustaining  life,  except  fat.  This  is  commonly  added  in  other 
articles  ot  diet,  especially  in  butter, — "bread  and  butter,"  conse- 
quently, forming  an  almost  perfect  article  of  food.  The  following 
experiment  is  recorded  :  "A  dog  eating  ad  libitum  of  white  bread, 
made  of  pure  wheat,  and  freely  supplied  with  water,  did  not  live 
beyond  fifty  days.  He  died  at  the  end  of  that  time  with  all  the 
signs  of  gradual  exhaustion."  Death  took  place,  not  because  there 
was  anything  hurtful  in  the  bread,  but  because  of  the  absence  of 
one  or  more  of  the  food  principles. 

w  27.  The  Potato. — The  common  or  Irish  potato  is  the  vegetable 
most  extensively  used  in  this  country  and  Great  Britain.  Among 
the  poorer  classes  in  Ireland  it  is  the  main  article  of  food.  While 
it  is  not  so  rich  in  nutritious  substances  as  many  others,  it  has  some 
very  useful  qualities.  It  keeps  well  from  season  to  season,  and 
men  do  not  weary  of  its  continuous  use.  It  is  more  than  two- 
thirds  water,  the  rest  being  chiefly  starch,  with  a  little  albumen. 

28.  The  sweet  potato  differs  from  the  white  or  common  in  con- 
taining more  water  and  a  small  proportion  of  sugar.     The  common 
potato  and  the  tomato  belong  to  the  same  botanical  order  as  the 
"  nightshades,"  but  do  not  possess  their  poisonous  qualities,  unless 
we  except  potatoes  that  are  in  the  process  of  germination  or  sprout- 
ing, when  they  are  found  injurious  as  food. 

29.  Fruits. — These   are    produced,   in   this   country,   in   great 
abundance,  and  are  remarkable  alike  for  their  variety  and  delicious 
flavor;  consequently  they  are  consumed  in  large  quantities,  espe- 
cially during  the   warmer  months.      The   moderate   use  of  ripe 
fruits,  in  their  season,  is  beneficial,  because  they  offer  a  pleasant 
substitute  for  the  more  concentrated  diet  that  is  used  in  cold 


26.  Wheaten  bread  ?    Bread  and  butter  ?    Experiment  on  the  dog  t 

27.  State  what  is  said  of  the  Irish  potato? 

28.  Sweet  potato?    Nightshades?    Potatoes  when  germinating ? 

29.  Fruits?    Use  of  ripe  fruit?    Nutriment  they  contain?    Starch  in  unripe  fruits! 
Ctooking  of  unripe  fruits? 


94  FOOD    AND    DRINK. 

weather.  The  amount  of  solid  nutriment  they  contain  is,  however, 
small.  The  percentage  of  water  in  cherries  is  seventy-five,  in 
grapes  eighty-one,  in  apples  eighty-two.  Unripe  fruits  contain 
starch,  which,  during  the  process  ot  ripening,  is  converted  into 
sugar  Such  fruits  are  indigestible,  and  should  be  avoided ;  cook- 
ing, however,  in  part  removes  the  objections  to  them. 

30.  Pure  Water— It  is  important  that  the  water  we  drink  and 
use  in  the  preparation  of  food  should  be  pure.     It  should  be  cleai 
and  colorless,  with  little  or  no  taste  or  smell,  and  free  from  any 
great  amount  of  foreign  ingredients.     Chemically  pure  water  does 
not  occur  in  nature;  it  is  obtained  only  by  the  condensation  of 
steam,  carefully  conducted,  and  is  not  as  agreeable  for  drinking 
purposes  as  the  water  furnished  by  springs  and  streams.     Kain- 
water  is  the  purest  occurring  in  nature;   but  even  this  contains 
certain  impurities,  especially  the  portion  which  falls  in  the  early 
part  of  a  shower ;  for  in  its  descent  trom  the  clouds,  the  particles 
floating  in  the  air  are  caught  by  the  tailing  drops. 

31.  Water  from  springs  and  wells  always  contains  more  or  less 
foreign  matter  of  mineral  origin.     This  imparts  to  the  drink  its 
pleasant  taste — the  sparkle,  or  "life,"  coming  from  the  gases  ab- 
sorbed by  the  water  during  its  passage  under  ground      The  ordi- 
nary supply  of  cities  is  from  some  pure  stream  or  pond,  conveyed 
from  a  distance  through  pipes,  the  limpid  fluid  containing  generally 
only  a  small  amount  of  impurity.     Croton  water,  the  supply  of 
New  York  City,  is  very  pure,  and  contains  only  four  and  a  half 
grains  to  a  gallon ;  the  Ridgewood  water,  of  Brooklyn,  hold?,  even 
less  foreign  matter. 

32.  Drinking-water  may  contain  as  large  a  proportion  as  sixty  to 
seventy  grains  per  gallon  of  impurity,  but  a  much  larger  quantity 
renders  it  unwholesome.     The  mineral  spring  waters,  used  popu 
larly  as  medicines,  are  highly  charged  with   mineral   substances. 
Some  of  them,  such  as  the  waters  at  Saratoga,  contain  three  hun- 
dred grains  and  more  to  the  gallon.    (Read  Note  11.) 

11.  Impure  Water  Spreads  Disease. — "In  the  year  1867,  three 

SO.  How  should  drinking-water  be  as  regards  color  and  smell?  Chemically  pure  water? 
How  obtained  ?  Agreeableness  of  perfectly  pure  water  ? 

81.  Spring  and  well  water  ?  Whence  the  sparkle,  or  life  ?  The  water  supply  of  citios? 
Croton  water?  Ridgewood? 

32.  impurities  in  drinking-water?    Mineral  springs? 


POOD    AND    DRINK.  95 

33.  Action  of  Water  upon  Lead. — The  danger  of  using  watei 
that  has  been  in  contact  with  certain  metals  is  well  known.  Lead 
is  one  of  the  most  readily  soluble,  and  probably  the  most  poisonous 
of  these  substances  in  common  use.  When  pure  water  and  an 
untarnished  surface  of  lead  come  in  contact,  the  water  gradually 
corrodes  the  metal,  and  soon  holds  an  appreciable  quantity  of  it  in 
solution.  When  this  takes  place  the  water  becomes  highly  inju- 
rious; the  purer  the  water,  and  the  more  recent  the  use  of  the 
metal,  the  greater  will  be  the  danger.  (Read  W"te  12.) 


millions  of  pilgrims,  of  whom  a  handful  had  come  from  a  cholera  district, 
assembled  at  Hurdwar,  a  few  miles  from  the  spot  where  the  Ganges  escapes 
from  the  Himalayas.  On  the  12th  of  April  the  three  millions  resolved  to 
bathe  and  drink.  *  The  bathing-place  of  the  pilgrims  was  a  space  650  feet 
long  by  30  feet  wide,  shut  off  from  the  rest  of  the  Ganges  by  rails.  Into  this 
long  and  narrow  inclosure  pilgrims  from  all  parts  of  the  encampment  crowded 
as  closely  as  possible  from  early  morn  to  sunset ;  the  water  within  this  space, 
during  the  whole  time,  was  thick  and  dirty — partly  from  the  ashes  of  the 
dead,  brought  by  surviving  relatives  to  be  deposited  in  the  water  of  their  river 
god,  and  partly  from  the  washing  of  the  clothes  and  bodies  of  the  bathers. 
Now,  pilgrims  at  the  bathing  ghaut,  after  entering  the  stream,  dip  themselves 
under  the  water  three  times  or  more,  and  then  drink  of  the  holy  water,  whilst 
saying  their  prayer.  The  drinking  of  the  water  is  never  omitted ;  and  when 
two  or  more  members  of  a  family  bathe  together,  each  from  his  own  hand 
gives  to  the  other  water  to  drink.  On  the  evening  of  the  next  day,  the  13th 
of  April,  eight  cases  of  cholera  were  admitted  into  one  of  the  hospitals  at 
Hurdwar.  By  the  15th,  the  whole  of  this  vast  concourse  of  pilgrims  had  dis- 
persed,' carrying  the  cholera  in  every  direction  over  India ;  it  attacked  the 
British  troops  along  the  various  routes,  it  passed  the  northern  frontier,  got 
into  Persia,  and  so  on  into  Europe,  where  it  will  work  its  wicked  will  for  some 
time  to  come.  That  is  a  sample  of  the  mischief  water  can  do  in  the  way  of 
spreading  disease. " — London  Medical  Press. 

12. (Lead  in  Drinking- Watey— "  The  danger  of  using  lead  for  pipes  or 
cisterns  is  now  well  known,  the  case  of  the  late  royal  family  of  France,  at 
Claremont,  having  made  the  matter  notorious.  In  this  case  there  was  one- 
tenth  of  a  grain  in  the  gallon,  and  one-third  of  the  persons  who  drank  the 
water  were  affected.  But  even  one  one-hundredth  of  a  grain  per  gallon  has 
produced  palsy  in  those  who  drank  this  impurity  habitually.  It  is  remarkable 
that  the  Thames  water  will  at  one  time  dissolve  lead,  and  not  at  another."— 
Ifapother's  Health  Lectures. 

83.  What  is  stated  of  the  action  of  water  upon  lead? 


96  POOD    AND    DRINK. 

34.  In  cities,  lead  pipes  are  commonly  used  to  convey  water 
through  the  houses;  lead  being  also  used  in  the  construction  of 
roofs,  cisterns,  and  vessels  for  keeping  water  and  other  liquids. 
After  articles  made  of  lead  have  been  in  use  several  months,  the 
danger  of  lead-poisoning  diminishes.     An  insoluble  coating  of  the 
sulphate  of  lead  forms  upon  the  exposed  surface,  thus  protecting  it 
from  further  corrosion.     It  is,  however,  a  wise  precaution,  at  all 
times,  to  reject  the  water  or  other  fluid  that  has  been  in  contact 
with  leaden  vessels  over  night,  or  for  a  number  of  hours.     Allow 
the  water  in  pipes  to  run  freely  before  using. 

35.  Coffee. — This  is  an  important  addition  to  diet,  and,  if  mod- 
erately used,  is  beneficial  to  persons  of  adulfc  age.     As  commonly 
employed,  it  consists  of  an  infusion  in  boiling  water  of  the  roasted 
and  ground  berry.     The  water  extracts  certain  flavoring  and  color- 
ing matters,  but  that  which  gives  it  its  peculiar  stimulant  qualities 
is  the  alkaloid  caffeine.     With  most  persons  its  action  is  that  of  a 
gentle  stimulant,  without  any  injurious  reaction.     It  produces  a 
restful  feeling  after  exhausting  efforts  of  mind  or  body;  it  tranquil- 
izes,  but  does  not  disqualify  for  labor,  and  hence   it  is  highly 
esteemed  by  persons  of  literary  pursuits. 

36.  Another  property  of  coffee  is,  that  it  diminishes  the  waste  of 
the  tissues,  and  consequently  permits  the  performance  of  excessive 
labor  upon  an  economical  and  inadequate   diet.     This  has   been 
tested  among  the  miners  of  Belgium.     Their  allowance  of  solid 
food  was  below  that  found  necessary  in  prisons  and  elsewhere ;  but, 
with  the  addition  of  about  four  pints  of  coffee  daily,  they  were 
enabled  to  undergo  severe  labor  without  reducing  their  muscular 
strength.     The  caravans  which  traverse  the  deserts  are  supported 
by  coffee  during  long  journeys  and  lengthened  privation  of  food. 
Among  armies  it  is  indispensable  in  supplementing  their  imperfect 
rations,  and  in  relieving  the  sense  of  fatigue  after  great  exposure 
and  long  marches.     When  taken  with  meals,  coffee  is  also  thought 
to  promote  digestion. 

84.  Lead  in  pipes  and  other  things  f  Advice  ?  What  takes  place  after  the  articles  of 
lead  have  been  used  much  ?  What  is  wise  ? 

35.  Coffee  as  an  article  of  diet  ?  Of  what  does  it  consist  ?  How  does  the  water  affect  the 
coffee  ?  The  peculiar  stimulant  ?  How  does  it  affect  most  persons  ? 

86.  Another  property  of  coffee  ?  Miners  of  Belgium  ?  The  Caravans  ?  Among  armies  f 
Taken  with  meals? 


POOD    AND    DRINK.  97 

37.  Tea. — The  effects  of  tea-drinking  are  very  similar  to  those  of 
coffee,  and  are  due  to  a  peculiar  principle  called  tlieine.     This  prin- 
ciple is  probably  the  same  as  that  found  in  coffee — caffeine — since  the 
chemical  composition  of  both  is  precisely  alike.    Tea,  as  a  beverage, 
is  made  from  the  dried  leaves  of  the  plant  by  the  addition  of  hot 
water;  if  the  tea  be  boiled,  the  oil  which  gives  it  its  agreeable 
flavor  is  driven  off  with  the  steam.     There  are  two  kinds  of  tea — 
the  black  and  the  green ;  the  latter  is  sometimes  injurious,  produc- 
ing wakefulness'and  other  nervous  symptoms.     The  excessive  use 
of  either  coffee  or  tea  will  cause  wakefulness. 

38.  During  Dr.   Kane's  expedition  in  the  Arctic  regions,  the 
effects  of  these  articles  were  compared.     "  After  repeated  trials,  the 
men  took  most  kindly  to  coffee  in  the  morning,  and  tea  in  the 
evening.     The  coffee  seemed  to  continue  its  influence  throughout 
the  day,  and  they  seemed  to  grow 'hungry  less  rapidly  than  after 
drinking  tea,  while  tea  soothed  them  after  a  day's  hard  labor,  and 
the   better   enabled   them   to   sleep.      They   both   operated   upon 
fatigued  men  like  a  charm,  and  their  superiority  over  alcoholic 
stimulants  was  very  decided." 

39.  Chocolate  is  made  from  the  seeds  of  the  cocoa-tree,  a  native 
of  tropical  America.     Its  effects  resemble  somewhat  those  of  tea  and 
coffee,  but  it  is  very  rich  in  nutriment.      Linnaeus,  the  botanist, 
was  so  fond  of  this  beverage,  that  he  gave  to  the  cocoa-tree  the 
name  Theobroma — "  the  Food  of  the  Gods."     Its  active  principle 
is  theobromin. 

40.  Alcohol. — The  word  alcohol  is  of  doubtful  origin.     It  is 
commonly  supposed  to  be  derived  from  the  Arabic  language,  several 
words  in  that  tongue  resembling  it  in  sound,  but  none  of  them  or 
any  other  in  the  language  have  a  meaning  corresponding  with  that 
of  the  English  term. 

41.  History. — Alcohol  was   distilled  from  rice  many  centuries 
before  that  seed  was  known  in  Europe.     We  hear  of  it  in  Bagdad 
about  the  year  900.     It  was  known  to  the  Moors  of  Spain,  through 

37.  Effects  of  tea-drinking?    Peculiar  principle?    The  tea  beverage,  how  made ?    Black 
and  green  tea  ?    Excessive  use  of  tea  or  coffee  ? 

38.  Experiments  made  during  Kane's  expedition? 
89.  State  what  is  said  of  chocolate. 

40.  In  what  language  has  the  word  alcohol  its  origin? 

41.  Give  its  history. 


98  POOD   AND    DRINK. 

whom  the  knowledge  of  its  production  spread  into  Western  Europe. 
The  first  description  of  alcohol  was  given  by  a  western  writer  about 
1280,  who  wrote  of  a  "  burning  01  ardent  water  "  that  resulted 
from  the  distillation  of  wine.  It  may  also  have  been  known  to  the 
Romans,  for  Pliny?  in  the  first  century,  wrote  of  a  strong  kind  of 
wine  that  was  inflammable — a  quality  that  strongly  suggests  the 
knowledge  of  a  product  of  distillation. 

42.  The  Alcohols. — There  are  at  least  twelve  members  of  the 
alcohol  family,  the  oldest  of  which  is*  common  alcohol.  This  last 
is  the  only  one  that  need  be  referred  to  here.  Common  Alcohol  is 
sometimes  known  .as  spirit  of  wine,  also  as  vinic  alcohol.  It  is 
commonly  obtained  by  the  distillation  of  grains  or  of  wine.  The 
ardent  spirits  of  commerce  (brandy,  whiskey,  gin,  and  rum)  contain 
about  one-  half  water,  the  other;.tyalf  alcohol.  Alcohol  is  also  found  in 
all  the  wines  and  malt  liquor^^r,  ale,  and  porter)  in  varying  propor- 
tions. The  juices  of  ripe,  sweet  fruits  will,  at  seventy  degrees  Fahren- 
heit, begin  spontaneously  to  "  work"  or  ferment;  also  wheat  and  other 
starch-grains,  when  sprouting,  will  have  their  starch  changed  into 
sugar,  and  this,  in  like  manner,  will  undergo  fermentation — alcohol 
being  one  of  the  results  of  this  action  in  both  cases.  Thus  this  fermen- 
tation, in  changing  barley,  grapes  and  apples,  into  beer,  wine  and  cider, 
respectively,  transforms  valuable  foods  into  most  seductive  poisons. 
43.  Properties  of  Alcohol.  — Alcohol  is  a  clear,  colorless,  vola- 
tile, and  inflammable  liquid  of  penetrating  odor  and  burning  taste. 
It  is  lighter  than  water.  As  it  cannot  be  frozen,  it  is  used  in  ther- 
mometers for  taking  low  or  exceedingly  cold  temperatures.  It  is 
also  used  in  spirit  levels.  It  burns  with  a  pale,  bluish  flame,  with- 
out smoke,  and  with  intense  heat ;  hence  its  use  in  the  spirit-lamp. 

44.  Is  Alcohol  Food  ? — Some  authorities  class  alcohol  among 
the  food  substances.  Chemically  it  is  allied  to  the  sugars,  but  the 
effect  of  alcohol  within  the  body  is  very  unlike  that  of  the  sugars. 
The  latter  are  nourishing,  while  the  former  tends  to  impair  nutri- 
tion. It  was  on  the  mistaken  theory  that  alcohol  had  sustaining 
power,  that  for  two  hundred  years  the  armies  and  navies  of  certain 
countries  were  supplied  with  rations  of  rum  or  some  other  alcoholic 


42.  How  is  common  alcohol  obtained  ? 

43.  What  are  the  properties  of  alcohol  ? 

44.  What  can  you  say  of  alcohol  a>  a  food? 


POOD    AND    DRINK.  99 

• 

drink,  under  the  name  of  "  grog."  During  recent  years,  a  systematic 
inquiry  has  been  made  to  discover  whether  the  grog-ration  was 
really  serviceable  or  the  reverse.  Tests  have  been  tried  upon  con- 
siderable bodies  of  men,  under  military  discipline,  by  withdrawing 
that  ration ;  comparisons  have  been  made  at  Ijome  and  abroad,  in 
hot  climates  and  in  cold,  in  active  service  and  at  rest.  The  results 
of  these  observations  have,  without  exception,  been  favorable  to 
the  non-use  of  spfc^ts.  The  proportion  of  ill-health,  the  number  of 
sick  days,  and  the  incapacity* for  work  have  invariably  been  greater 
among  the  men  to  whom  the  spirit-ration  has  been  issued,  the  qual- 
ity of  food  and  other  circumstances  being  maife  as  nearly  equal  as 
possible.  Hence  the  conclusion  that  not  only  is  alcohol  not  a  food, 
but  is  injurious  in  itself,  and  a  detrarient  to  the  food  taken. 

45.  Does  Alcohol  Relieve  Thi^  ?— One  of  the  most  striking 
properties  of  alcohol  is  its  affinity  for  water.    When  swallowed,  there- 
fore, its  tendency  is  to  deprive  the  body  of  water,  and  to  create 
thirst  rather  than  to  relieve  H.     It  may  then  be  stated  that  alcoholic 
drinks  which  appear  to  quench  thirst  do  so  by  means  of  the  water 
bhat,  in  greater  or  less  quantities,  dilutes  the  alcohol  they  contain. 
Water,  the  peerless  beverage  of  nature,  does  its  work  better  in  pro- 
portion as  it  remains  free  from  alcohol.     To  maintain  normal  ac- 
tion, the  delicate  organs  of  the  body  require  a  uniform  supply  of 
water.     When  alcohol  is  introduced,  it  draws  the  water  to  itself, 
and  leaves  the  organs  without  their    share    of  proper  moisture ; 
hence,  after  death  from  alcoholism,  we  find  them  affected  in  dif- 
ferent degrees,  being  drier  and  harder  than  is  natural. 

46.  Does  Alcohol  Enable  its  Consumers  to  Resist  Extreme 
Cold  ? — If  this  could  be  proved  to  be  a  fact,  some  of  its  boasted 
usefulness  would  receive  support.     In  extremely  cold  climates,  the 
inhabitants  are  enabled  to  live   comfortably   by  consuming  vast 
quantities  of  animal  food  alone,  especially  if  it  is  abundantly  oily. 
Will  alcohol  act  in  a  similar  way  or  assist  in  maintaining  heat? 
Experience  and  observation  say  no. 

47.  Before  the  thermometer  was  applied  to  the  testing  of  the 
body's  temperature,  it  was  commonly  supposed,  by  reason  of  the 

45.  Does  alcohol  relieve  thirst? 

46.  Does  alcohol  enable  one  to  resist  cold  ? 

47.  How  is  tt»e  temperature  of  the  body  affected  ? 


100  POOD    AND   DRINK. 

sensations  of  warmth,  that  alcohol  increased  bodily  heat.  When, 
however,  this  new  test  was  applied,  it  became  apparent  that  those 
sensations  were  deceptive,  and  that  there  had  been  an  actual  fall  in 
temperature  as  the  result  of  imbibing  alcohol.  The  surface  of  the 
stomach  is  irritated  by  this  powerful  agent,  causing  the  nerves  of 
sensation  to  convey  to  the  brain  the  impression  that  something  has 
entered  the  stomach  which  is  producing  warmth.  This  is  a  delusive 
impression,  as  we  know,  by  pouring  a  few  drops  of  alcohol  on  the 
skin,  that  the  tendency  of  alcohol  is  to  cool  the  surface  whenever 
evaporation  can  take  place. 

48.  The  sensation  of  warmth  of  the  face  and  surface  of  the  body 
is   also   deceptive.     The   flushing   of   the   face,    common   to  hard 
drinkers,  does  not  indicate  that  they  have    a  superabundance  of 
animal  heat,  the  temperature  ol,;-their  bodies  being  below  normal. 
The  true  cause  of  the  flush  is  a  paralysis  of  one  set  of  nerves  govern- 
ing the  natural  action  of  the  hair-like  vessels  that  course  just  below 
the  skin.     Nature  has  provided  these  infinitely  fine  vessels  with 
minute  controlling  nerves,  whose  duty  it  is  to  regulate  the  flow  of 
blood  in  exposed  positions.     Alcohol  paralyzes  this  control;  the 
blood  flows  at  random,  and  the  terminal  vessels  are  overcharged 
with  blood.      Hence,  the  high  color,  which  is  so  remarkable  in 
habitual  drinkers  that  it  amounts  to  a  disfigurement  is  Nature's 
signal  of  distress,  showing  that  the  circulation  is  deranged,  and  the 
blood  is  unduly  brought  into  contact  with  the  lower  temperature  of 
the  outer  air.     Alcohol,  therefore,  is  not  a  producer  of  heat,  but  a 
promoter  of  cold,  and  must  be  dangerous  to  any  persons  taking  it 
when  they  are  exposed  to  low  temperatures.     (Read  Note  13.) 

49.  The  testimony  of  those  who  have  had  experience  in  contact 
with  the  realms  of  snow  and  ice  is  unanimous  against  the  cold- 

13.  Dr.  Rae's  Statement—"  The  Arctic  explorer,  Dr.  Rae,  states  that  he 
found  entire  avoidance  of  alcohol  necessary  in  the  far  North.  The  moment  a 
man  had  swallowed  a  drink  of  spirits,  it  was  certain  that  his  day's  work  was 
nearly  at  an  end.  '  It  was  absolutely  necessary  that  the  rule  of  total  absti- 
nence should  be  rigidly  enforced,  if  we  would  accomplish  our  day's  task.  Any 
use  of  liquor,  as  a  beverage,  when  we  had  work  on  hand,  in  that  terrific  cold* 
was  out  of  the  question.'  * 

48.  Of  what  is  the  flushed  fact  of  drinkers  the  index? 
«&  Vftjat  <Jo  travelers  in  cold  countries  say  of  it*  usel 


.- 

FOOD    AND    DRINK.  101 

resisting  property  of  alcohol.  It  is  recorded  of  the  men  who 
served  in  Napoleon's  campaign  in  Russia,  under  great  exposure  to 
cold,  that  death  was  hastened  by  the  use  of  alcohol.  The  evidence 
of  the  Monks  of  St.  Bernard  is  similar.  Numerous  Arctic  explorers 
testify  that  not  only  is  the  temporary  indulgence  liable  to  result  ID 
most  serious  consequences,  but  that  strong,  able-bodied  men  in  the 
habit  of  using  alcoholic  drinks  are  entirely  unfitted  to  resist  the 
cold  to  which  they  must  be  exposed.  The  natives  and  travelers 
alike  rely  upon  fresh  animal  food,  especially  fatty  food,  and  avoid 
alcohol  as  a  danger  to  life.* 

50.  Alcohol  Destructive  to  Life. — Instead  of  being  a  promoter 
of  life,  as  the  early  alchemists  who  produced  it  hoped  it  woidd  be, 
alcohol  is  hostile  to  life ;  it  is  a  poison.     Plant  life  is  speedily  de- 
stroyed when  brought  into  close  contact  with  it.     The  lower  animals 
Are  poisoned  by  it.     When  applied  directly  to  small  insects  and 
reptiles,  death  commonly  occurs  in  a  few  seconds  or  minutes.     It  is 
hurtful  to  the  larger  animals,  and  the  more  intelligent  of  them 
appear  to  resent  its  use  instinctively.     This  is  seen  when  dogs  have 
been  forced  to  take  brandy  in  small  doses  for  some  time.     Instead 
of  learning  to  like  it,  they  gradually  show  a  greater  and  greater  dis- 
like to  it. 

51.  The  Proper  Use  of  Alcohol. — Like  opium,  chloral,  arsenic, 
and   many  other   poisons,  alcohol   may  be  rightly  used,  and  that 
is  as  a  medicine.     For  the  relief  of  sickness  and  feebleness  of  body, 
or  conditions  of  unusual  fatigue,  alcohol  can  be  beneficially  used 
under  the  advice  of  a  physician.     Like  the  other  poisons,  it  should 
be  definitely  prescribed  and  the  size  and  number  of  the  doses  pre- 
cisely ordered  by  the  physician. 

*  "Alcohol  is  not  the  warming  cordial  and  invigorating  stimulant  that  it 
is  reputed  to  be,  but  there  is  a  world-full  of  preconceived  opinions  in  its  favor 
that  must  b<3  met  and  overcome  before  the  true  view  can  make  its  way.  But 
the  truth'  must  prevail  at  last.  Its  true  place  is  not  along  with  the  displays 
of  wealth  and  luxury  upon  our  sideboards,  but  in  the  medicine-chest  along 
with  hasheesh,  henbane,  opium,  stramonium,  and  so  forth,  labeled  as  a  POJ« 
SON  ! " — Dr.  A.  F.  Kinne. 


60.  What  is  the  affect  of  alcohol  upon  life? 
W.  What  is  the  proper  use  of  alcohol  i 


102  FOOD    AND    DRINK. 

52.  Errors  in  the  Use  of  Alcohol. — If  this  view  of  the  question 
is  the  correct  one,  how  utterly  foolish  is  the  practice  of  those  who 
are  continually  prescribing  for  themselves  doses  of  this  poisonous 
substance  for  any  trifling  disturbance  of  their  health.     And  how 
much  worse  is  the  practice  of  taking  the  various  forms  of  alcohol 
whan  the  person  so  taking  them  is  in  good  health  and  merely  in- 
dulges in  drinking  for  the  purpose  of  bringing  about  a  temporary 
stimulation.     And  worse  than  all  the  others  is  the  practice  of  those 
who  not  only  indulge  in  these  stimulants  themselves,  but  who  ask 
others  to  join  in  with  them  under  the  name  of   good-fellowship, 
when  none  of  them  are  to  be  benefited  by  so  doing,  but  rather  all 
of  them  are  in  danger  of  being  injured  by  the  act. 

53.  This  practice,  last  referred  to,  is  often  mistakeiily,£goken  of  as 
a  sign  ot  generosity,  and  is  ordinarily  called  "  treating."    It  is  wholly 
indefensible  from  a  physiological  point  of  view,  being  harmful  boj,h 
to  body  and  mind ;  and  from  a  social  point  of  view  is  withou't  its 
equal  for  the  evil  that  it  has  wrought  and  is  capable  of  working 
The  "social  glass  "and  the  "treat  at  the  bar"  count  a  hundred 
victims  to  every  other  single  one  that  can  be  traced  to  any  other 
mistaken  practice  of  human  society.     It  is  in  regard  to  the  evils 
that  flow  from  this  false  show  of  generosity  and  geniality  that  the 
minds  of  the  young  should  early  be  instructed.     It  is  a  well  estab- 
lished fact  that,  in  some  people,  alcohol  has  the  power  to  create  a 
craving  for  more.     Their  nervous  systems  become  so  easily  poisoned 
by  its  use  that  they  must  have  more,  and  they  have  not  the  will- 
power to  resist   the  temptation.     This  tendency  to  be  so   easily 
poisoned  is  also  hereditary  in  some  families,  producing  drunkards 
for  several  generations. 

54.  Moderation  Societies. — "  Moderation  societies  "  have  been 
organized  to  check  the  evils  of  "  treating,"  but  they  have  not  met 
with  success,  and  it  is  not  to  be  expected  that  they  will,  for  there 
can  be  no  moderation  in  the  use  of  this  dangerous  drug  except  in 
the  way  mentioned  at  the  beginning  of  this  section,  namely,  as  a 
prescribed  medicine.     As  Dr.  Alden  has  said,  "  There  is  no  such 


52.  What  three  errors  mentioned  ? 

53.  What  is  said  of  treating?    Is  alcohol  deceptive f 
$4.  What  is  said  of  moderation  societie.3? 


FOOD   AND   DRIS 

P.  Ay^o  D  M 

thing  as  a  temperate  use  of  spirits.  In  any  quantity  th'ey  are  an 
enemy  to  the  human  constitution.  Their  influence  upon  the  phys- 
ical organs  is  unfavorable  to  health.  They  produce  weakness,  not 
strength  ;  sickness,  not  health ;  death,  not  life." 

55.  Diminished  Use  of  Alcohol  as  Medicine. — As  a  medicine, 
alcohol  is  far  less  freely  used  by  physicians  now  than  formerly.    The 
dangers  from  its  use  are  more  generally  recognized,  and  other  reme- 
dies have  been  discovered  and  brought  into  use  that  are  fully  as 
efficient  and  active,  but  have  not  the  tendency  to  habit-forming  that 
is    so   peculiar   to   alcohol  and  other  narcotics.      There   are   able 
physicians  who  refuse  to  employ  every  form  of  alcohol  as  stimu- 
lant or  medicine,  in  the  belief  that  it  can  be  safely  and  happily 
replaced   by  other  remedies.      In  London  and  some   other  cities, 
hospitals  have  recently  been   organized  and  are  now  being  oper- 
ated  on   the   basis   of  total  abstinence  from  alcoholic  treatment. 
In  many  parts  of  England  the  use  of  alcohol  has  greatly  declined 
in  the  alms-houses  and  other  public  institutions,  in  which  formerly 
the  amount  of  stimulants  annually  consumed  was  very  great. 

56.  It  is  well  known  that  alcohol  is  an  ingredient  in  many  of  the 
"  Bitters"  and  other  so-called  patent  medicines  that  have  come  into 
popular  use  through  advertisement  in  the  newspapers.     Many  per- 
sons have  been  deluded  into  the  use  of  these,  to  them,  doubly 
bitter  substances ;  for,  not  only  have  they  not  found  the  curative 
results  falsely  proclaimed  in  the  papers,  but  they  have  been  be- 
guiled into  habits  of  drinking  and  into  a  liking  for  alcohol  that 
the  "  bitters  "  soon  fail  to  satisfy. 

57.  Concerning  the  Purity  of  Alcoholic  Beverages. — It  is  well 
known  that  many  makers  and  friends  of  wines  and  liquors  claim 
that  when  these  articles  are  pure  they  are  not  injurious,  but  that 
they  become  hurtful  after  they  leave  their  place  of  manufacture  by 
reason  of  the  impurities  that  are  added  to  them  by  unscrupulous 
dealers.     'c  Pure  and  good  liquor,"  they  say,  "  does  no  harm."     Is 
this  correct  ?     It  cannot  be  denied  that  deadly  additions  have  been, 
and  may  be,  so  made  that  these  beverages  will  become  more  speedily 


65.  Is  alcohol  as  highly  valued  in  medicine  now  as  formerly? 

66,  The  effect  of  Bitters? 

St.  What  do  wine-dealers  say  ?    What  is  the  harmful  element? 


103a  POOD    AND    DRINK. 

and  manifestly  poisonous  than  they  would  otherwise  be,  but  the 
teaching  of  modern  physiology  is  this :  that  so  long  as  the  main 
element  of  danger — that  same  alcohol  from  which  they  get  their 
stimulating  and  seductive  properties — is  present,  the  question  of 
purity,  or  age,  or  smoothness  of  taste  is  one  of  little  importance. 
The  "  unclean  thing,"  as  the  Bible  calls  it,  is  present  in  all  intoxi- 
cants, whether  they  be  old  and  costly,  or  cheap  and  new  and  fiery 
to  the  taste.  (Read  Note  14.) 

58.  This  so-called  "  purity "  is  commonly  an  accompaniment  of 
high  cost,  especially  as  applied  to  wines,  and  represents  money  or 
capital  that  has  been  long  lying  idle  in  order  that  the  commodities 
in  question  may  acquire  "age"  and  smoothness  to  the  palate. 
"  Purity  "  is  therefore  largely  the  cry  of  the  seller,  who  is  anxious 
to  get  back  his  invested  capital,  with  interest,  or  perhaps  with 
usury.  It  should  be  clearly  understood  that  the  best  of  these 
drinks,  even  though  obtained  from  the  vineyards  or  wine-cellars 
of  princes,  are  injurious,  and  that  the  word  "purity"  is,  in  the 
light  of  science,  a  misnomer  when  applied  to  any  beverage  that 
contains  alcohoL  (Read  Note  15.) 


14.  Adulteration  in  Liquors. — "It  is  not  enough  that  alcoholic  drinks 
are  dangerous  when  purely  made,  but  there  is  an  added  danger  growing  out  of 
the  almost  universal  practice  of  the  manufacturers  of  these  drinks  to  tamper 
with  them  and  adulterate  them  with  other  harmful  materials.  Not  many 
months  ago  the  city  government  of  Paris  caused  a  testing  of  all  the  wines 
that  were  brought  into  the  market  during  a  month  ;  there  were  1,518  samples 
of  French  wine  examined,  and  only  65  found  absolutely  free  from  injurious 
addition — that  is,  less  than  5  per  cent,  was  really  pure." — N.  Y.  Scientific 
Times. 

15.  Adulteration  of  Wine. — The  difficulty  in  the  way  of  getting  pure 
wine  is  nothing  new.  Pliny,  who  lived  eighteen  hundred  years  ago,  wrote 
the  following  complaint :  "  Let  us  suppose  that  we  all  agree  as  to  what  wine 
is  the  best,  how  shall  we  get  it  ?  Our  very  princes  do  not  drink  pure  wine  ; 
to  such  a  point  has  the  villainy  of  the  producers  and  sellers  of  wine  arrived 
that  we  can  buy  nothing  more  than  the  name  of  a  vintage — from  the  very 
wine- vat  it  is  all  adulterated — and  so,  marvellous  to  tell,  we  may  say  of  wine, 
the  poorer,  the  purer.** 


*8.  What  is  said  ot  purity  as  a  commercial  term  ? 


QUESTIONS    FOR    TOPICAL    REVTEW. 

.    >K^  PAO, 

1.  How  is  the  necessity  for  food  shown  ? , 81 

2.  To  what  process  of  waste  and  rapair  is  the  body  constantly  subjected  ? 81 

3.  How  do  you  account  for  the  sensations  of  hunger  and  thirst  ?. 82 

4.  What  further  can  you  state  having  relation  to  the  subject  ? 82 

5.  What  can  you  state  in  regard  to  the  quantity  of  food  required  for  the  support  of  life  ?  83 

6.  What  circumstances  change  the  needs  of  persons,  old  and  young,  as  regards  food 

and  drink? 83 

7  What  becomes  of  all  the  food  and  drink  we  consume? 85 

a  What  further  can  you  state  in  relation  to  the  process  of  renovation  through  which 

the  body  passes  ?... 85 

9,  What  can  you  state  of  the  habit  of  nations  in  respect  to  diet  ? 85 

10.  What  in  relation  to  the  selection  of  articles  for  food? 86 

11.  What  has  been  proved  as  regards  animal  food  ? 86 

12.  What  as  respects  the  necessity  for  changing  or  varying  the  diet  ? 87 

13.  Of  what  importance  is  milk  as  an  article  of  food  ? 87 

14.  Whatare  the  constituents  of  milk?..     87 

15.  What  can  you  state  of  eggs  as  an  article  of  food? 88 

16.  Of  the  meats,  so  called,  as  an  article  of  food? 88 

17.  What  effect  does  cold  have  upon  meats? 89 

18.  In  what  other  way  may  beef  and  pork  be  preserved  ? 89 

19.  What  can  you  state  of  salted  meat  as  food,  and  of  its  continued  use  ? 89 

20.  What  change  does  meat  undergo  in  the  cooking  ? 89,  90 

21.  What  directions  are  given  for  boiling  meat? 89 

22.  What  for  roasting,  and  with  what  results  ?  90 

23.  What  is  said  about  the  frying  of  meats? 90,91 

24.  Give  the  statement  in  relation  to  trichina 91 

25.  State  what  is  said  in  relation  to  fish 91 

26.  What  is  stated  of  the  usefulness  and  other  properties  of  the  products  of  the  vege- 

table kingdom  ? 91 

27.  What  further  is  said  of  vegetable  food? 91 

28.  Why  is  bread  made  of  wheat-flour  so  important  as  an  article  of  food  ? 92 

29.  State  whatever  else  you  can  in  relation  to  bread 92,93 

30.  Give  the  statement  respecting  the  potato 93 

31.  What  is  stated  of  fruits,  the  use  of  them,  their  nutritious  qualities,  etc 93 

82.  How  general  is  the  existence  of  perfectly  pure  water?. 94 

83.  What  is  stated  in  relation  to  drinking  water  ? 94 

84.  What  effect  has  the  action  of  water  upon  lead? 95 

85.  What  further  can  you  state  on  the  subject? 96 

86.  What  properties  has  coffee  as  an  article  of  diet? .....  96 

87.  In  what  circumstances  has  coffee  been  found  peculiarly  beneficial  ? 96 

88.  What  comparison  is  made  between  coffee,  tea,  and  chocolate  ? 97 

39.  How  are  the  wines,  and  malt,  and  other  alcoholic  beverages  produced  ? 97,  98 

40.  What  articles  are  employed  in  their  production  ? 98 

41.  What  are  the  properties  of  alcohol? 98 

42.  Is  alcohol  a  fbod? 98 

43.  What  is  said  of  the  property  of  alcohol  to  relieve  thirst? 99 

44.  What  effect  does  alcohol  have  upon  the  body's  temperature? 89 

45.  What  is  the  cause  for  flushing  of  face  in  drinkers? 100 

46.  What  is  the  testimony  of  Arctic  explorers  and  others? 100, 101 

47.  What  the  effect  of  alcohol  upon  plant  and  animal  life? 101 

48.  What  are  the  only  conditions  for  use  of  alcohol? 101 


OHLAJPTBIR    "VI. 

DIGESTION. 

The  Principa2  Processes  of  Nutrition — The  General  Plan  of  Digestion — Masfica- 
twn—The  Teeth— Preservation  of  the  Teeth— Action  of  the  Saliva— The 
Stomach  and  the  Gastrij  Juice — The  Movements  of  the  St-omach — Gastric 
Digestion — The  Intestines — The  Bile  and  Pancreatic  Juice, — Intestinal  Di- 
gestion— Absorption  by  means  of  Blood-vessels  andLacteals — The  Lymphatic 
or  Absorbent  System — The  Lymph — Conditions  which  affect  Digestion — The 
Quality,  Quantity t  and  Temperature  of  the  Food — The  Influence  of  Exer- 
cise and  Sleep — The  Kidneys — The  Spleen — Effect  of  Alchohol  on  Digestion, 
the  Liver,  and  Kidneys. 

1.  Nutrition. — The  great  design  of  food  is  to  give  nutrimertl  or 
nourishment  to  the  body.     But  this  is  not  accomplished  directly,  as 
the  food  must  first  pass  through  certain  preparatory  changes,  as 
follows :  (1),  Digestion,  by  which  the  food  is  reduced  to  a  soluble 
condition ;  (2),  Absorption,  by  which,  when  digested,  it  is  taken 
into  the  blood ;  (3),  Circulation,  which  carries  the  enriched  blood 
to  the  various  parts  of  the  system ;  and  (4),  Assimilation,  by  which 
each  tissue  selects  from  the  blood  the  materials  necessary  for  its 
support. 

2.  By  these  four  steps  the  sustaining  power  of  food  is  gradually 
brought  into   exercise  and  the  vital  machinery  kept  in  working 
order,  somewhat  after  the  manner  of  the  steam-engine.     To  operate 
the  latter,  the  force  imprisoned  within  the  coal  and  water  is  set  free 
and  converted  into  motion  by  the  burning  of  the  fuel  and  the  vapor- 
ization of  the  water.     It  will  be  seen,  however,  when  we  come  to 
study  these  operations  in  the  human  body,  that  they  are  conducted 
silently  and  harmoniously,  with  marvellous  delicacy  and  complete- 
ness, and  without  that  friction,  and  consequent  loss  of  power,  which 
attend  the  working  of  the  most  perfect  machinery  of  man's  inven- 
tion. 

1.  Design  ot  food  }    How  accomplished  ? 

1  Sustaining  power  of  food  ?    Simile  of  the  engine!    Operation  in  the  human  body? 


DIGESTION 


105 


3.  General  Plan  of  Digestion.— The  great  change  which  food 
undergoes  in  digestion  is  essentially  a  refining  process,  reducing 
articles  of  diet,  which  are  at  first  more  or  less  solid,  crude,  and 
coarse,  to  a  liquid  and  finely  comminuted  condition,  suitable  fox 
absorption  into  the  blood.     The  entire 

process  of  digestion  takes  place  in  what 
is  called  the  "  alimentary  canal,"  a  nar- 
row, crooked  tube,  about  thirty  feet  in 
its  entire  length.  This  canal  begins  in 
the  mouth,  extends  thence  downward 
through  the  gullet  to  the  stomach  (a  re- 
ceptacle in  which  the  principal  work  of 
digestion  is  performed),  and  thence  on- 
ward through  the  small  and  large  intes- 
tines. 

4.  The  stomach  and  intestines  are 
situated  in  the  cavity  of  the  abdomen 
(Fig.  20,  C,  and  Fig.  26),  and  occupy 
about  two-thirds  of  its  space.     The  ac- 
tion to  which  the  food  is  subjected  in 
these  organs  is  of  two  kinds — mechani- 
cal and  chemical     By  the  former  it  is 
softened,  agitated,  and  carried  onward 
from  one  point  to  another ;  by  the  lat- 
ter it  is  changed  in  form  through  the 
solvent  power  of  the  various  digestive 
fluids. 

5.  Mastication. — As  soon  as   solid 

food  is  taken  into  the  mouth,  it  undergoes  mastication  or  chewing. 
It  is  caught  between  the  opposite  surfaces  of  the  teeth,  and  by  them 
is  cut  and  crushed  into  very  small  fragments.  In  the  movements 
of  chewing,  the  lower  jaw  plays  the  chief  part ;  the  upper  jaw,  hav- 
ing almost  no  motion,  acts  simply  as  a  point  01  .resistance,  to  meet 
the  action  of  the  former.  These  movements  of  the  lower  jaw  are 

8.  Change  of  food  In  digestion  ?    Process  of  digestion  ?    Describe  the  alimentary  canal. 

4.  Situation  of  the  stomach  and  intestines?    Action  of  the  food?    Mechanical  action  1 
Chemical? 

5.  Describe  the  process  of  mastication.    How  many  and  what  movements? 


FIG.  20.— SECTION  OF  THE  TRUNK, 
SHOWING  THE  CAVITIES  OF  THK 
CHEST  AND  ABDOMEN. 


108 


DIGESTION. 


ot  three  sorts :  an  np-and-down  or  cutting,  a  lateral  or  grinding,  a  ad 
a  to-and-fro  or  gnawing  motion. 

6.  The  teeth  are  composed  of  a  bone-like  material,  and  are  h.eld 
in  place  by  roots  running  deeply  into  the  jaw.  The  exposed  por- 
tion, or  "  crown,"  is  protected  by 
a  thin  layer  of  enamel  (Fig.  21,  a). 
the  hardest  substance  in  the  body, 
and,  like  flint,  is  capable  of  strik- 
ing fire  with  steel.  In  the  interior 
of  each  tooth  is  a  cavity,  contain- 
ing blood-vessels  and  a  nerve, 
which  enter  it  through  a  minute 
opening  at  the  point  of  the  root 
(Fig.  23). 

7.  There  are  two  sets  of  teeth ; 
first,  those  belonging  to  the  earlier 
years  of  childhood,  called  the  milk 
teeth,  which  are  twenty  in  number 
and  small.  At  six  or  eight  years 
of  age,  when  the  jaw  expands,  and 
when  the  growing  body  requires  a 
more  powerful  and  numerous  set, 
the  roots  of  the  milk  teeth  are  ab- 
sorbed, and  the  latter  are  "  shed," 
or  fall  out,  one  after  another  (Fig. 
22),  to  make  room  for  the  permanent  set. 

8.  There  are  thirty-two  teeth  in  the  permanent  set,  an  equal 
number  in  each  jaw.  Each  half-jaw  has  eight  teeth,  similarly 
shaped  and  arranged  in  the  same  order ;  thus,  two  incisors,  one 
canine,  two  bicuspids,  and  three  molars.  The  front  teeth  are  small, 
sharp,  and  chisel-edged,  and  are  well  adapted  for  cutting  purposes ; 
hence  their  name  incisors.  The  canines  stand  next,  one  on  each 
Bide  of  the  jaw ;  these  receive  their  name  from  their  resemblance 
to  the  long,  pointed  tusks  of  the  dog  (Fig.  23). 

<J.  Composition  of  the  teeth  ?    Enamel  of  the  teeth  ?    Interior  of  teeth  ? 
7.  The  milk  teeth?    The  permanent  teeth? 
8,9.  Number  of  teeth  ?    How  arranged? 


FlQ.  21.— {SECTION  OF  A  TOOTH. 

c.  Enamel ;  6,  Cavity ;  c  c,  Roots ; 
d,  Body  of  the  Tooth. 


DIGESTION. 


107 


9.  The  bicusp.  ,j,  i:ext  in  order,  are  larger  and  have  a  broader 
crown  than  the  former;  while  behind  them  are  the  molars,  the 
largest  and  most  powerful  of  the  entire  set.  These  large  back 


2     1' 


PIG.  22.— SECTION  OP  THE  JAWS. 
1'  2'  y  4T  5',  The  Milk  Teeth  ;  1"  to  8",  The  Germs  of  the  Permanent  Set 

teeth,  or  "  grinders,"  present  a  broad,  rough  surface,  suitable  for 
holding  and  crushing  the  food.  The  third  molar,  or  "wisdom  tooth," 
is  the  last  to  be  cut,  and  does  not  appear  until  about  the  twenty- 
first  year.  The  arrangement  of  the  teeth  is  indicated  by  the  fol- 
lowing dental  formula : 


10.  It  is  interesting,  at  this  point,  to  notice  the  different  forms 

10.  Different  forms  of  teeth?    Human  teeth?  The  inference? 


108 


DIGESTION. 


of  teeth  in  different  animals,  and  observe  how  admirably  their 
teeth  are  suited  to  the  respective  kinds  of  food  upon  which  they 
feed.  In  the  carnivora,  or  flesh-feeders,  the  teeth  are  sharp  and 
pointed,  enabling  them  both  to  seize  their  prey  and  tear  it  in  pieces  ; 


Pio.  23.— SECTION  OF  THE  JAWS— RIGHT  SIDE. 

V,  A,  N,  Veins,  Arteries,  and  Nerves  of  the  Teeth.  The  root  of  one  tooth  in  each  jaw  is  cut 
vertically  to  show  the  cavity  and  the  blood-vessels,  etc.,  within  it.  1  to  8,  Permanent 
Teeth. 

while  the  herbivora,  or  vegetable-feeders,  have  broad,  blunt  teeth, 
with  rough  crowns,  suitable  for  grinding  the  tough  grasses  and 
grains  upon  which  they  feed.  Human  teeth  partake  of  both  forms ; 
some  of  them  are  sharp,  and  others  are  blunt ;  they  are  therefore 
well  adapted  for  the  mastication  of  both  flesh  and  vegetables, 


DIGESTION.  109 

Hence  we  infer  that,  although  man  may  live  exclusively  upon  either 
vegetable  or  animal  food,  he  should,  when  possible,  choose  a  diet 
made  up  of  both  varieties. 

11.  Preservation  of  the  Teeth.— In  order  that  the  teeth  shall 
remain  in  a  sound  and  serviceable  condition,  some  care  is  of  course 
requisite.     In  the  first  place,  they  require  frequent  cleansing ;  for 
every  time  we  take  food,  some  particles  of  it  remain  in  the  mouth, 
and  these,  on  account  of  the  heat  and  moisture  present,  soon  begin 
to  putrefy.     This  not  only  renders  the  breath  very  offensive,  but 
promotes  decay  of  the  teeth. 

12.  The  saliva,  or  moisture  of  the  mouth,  undergoes  a  putrefac- 
tive change,  and  becomes  the  fertile  soil  in  which  a  certain  minute 
fungus  has  its  growth.     This  fluid,  too,  if  allowed  to  dry  in  the 
mouth,  collects  upon  the  teeth  in  the  form  of  an  unsightly,  yellow 
concretion,  called  tartar.     To  prevent  this  formation,  and  to  remove 
other  offensive  substances,  the  teeth  should  be  frequently  cleaned 
with  water,  applied  by  means  of  a  soft  tooth-brush.     The  preven- 
tion of  the  tartar  fungus  is  best  effected  by  the  use  of  a  weak  solu- 
tion of  carbolic  acid.     (Read Note  l.} 

I.  The  Proper  Care  of  the  Teeth. — "  In  the  famous  history  of  Don 
Quixote,  the  hero  of  La  Mancha,  it  is  related  that  at  the  end  of  one  of  his 
great  battles,  wherein  he  was  as  usual  conquered,  he  found  himself  wounded 
in  the  face  by  a  violent  blow  from  a  stone,  and  grieved  to  find  that  with  it  he 
had  lost  one  of  his  teeth.     Reflecting  awhile  on  this  unhappy  accident,  he 
sagely  remarked  that  to  lose  a  molar  was  very  much  like  losing  an  old  friend. 
And  it  is  an  important  question,  in  view  of  this  bit  of  wisdom,  how  to  care  for 
the  molars,  that  they  may  become  old  friends.     To  this  end,  the  cardinal 
maxim  is  cleanliness  ;  and  again  cleanliness.     One  means  of  cleansing  is  the 
natural  one — that  is,  by  chewing  food  ;  for  it  is  well  known  that  if  we  have  a 
tooth  so  situated  in  the  jaw  that  it  is  seldom  brought  into  use,  that  tooth  early 
shows  signs  of  decay.     But  more  effectual  is  the  artificial  means — the  brush. 
Children  should  early  be  taught  to  use  this ;  and  for  them  a  softer  brush 
should  be  selected  than  for  adults.     They  should  also  early  be  taught  to  use 
no  metallic  substances,  as  pins,  needles,  etc.,  to  remove  substances  from  be- 
tween the  teeth.     The  teeth  should  always  be  thoroughly  cleansed  after  taking 
acids  into  the  mouth — for  they  are  the  great  enemies  to  the  teeth — and  also 
after  candies  and  other  forms  of  sugar,  for  their  particles  that  linger  on  the 

II.  Cleaning  of  teeth  ?    Effects  of  not  cleaning  ? 

12.  Effects  of  the  saliva  ?    Formation  of  tartar  ?    How  prevented  ?    How  destroyed? 


110  DIGESTION. 

13.  It  should  be  borne  in  mind  that  the  enamel,  Nature's  protec- 
tion for  the  teeth,  when  once  destroyed,  is  never  formed  anew ;  and 
the  body  of  the  tooth  thus  exposed  is  liable  to  rapid  decay.     On  this 
account,  certain  articles  are  to  be  guarded  against ;  such  as  sharply 
acid  substances  that  corrode  the  enamel,  and  hard  substances  that 
break  or  scratch  it — as  gritty  tooth-powders,  metal  tooth-picks,  and 
the  shells  of  hard  nuts.      Sudden  alternations  from  heat  to  cold, 

.JwrhEii>eating  or  drinking,  also  tend  to  crack  the  enamel. 

14.  Action  of  the  Saliva. — While  the  morsel  of  food  is  cut  and 
ground  by  the  teeth,  it  is  at  the  same  time  intimately  mixed  with 

the  saliva,  or  fluids  of  the 
mouth.  This  constitutes 
the  second  step  of  diges- 
tion, and  is  called  insali- 
vation.  The  saliva,  the 
first  of  the  digestive  solv- 
ents, is  a  colorless,  wa- 
tery, and  frothy  fluid.  It 
is  secreted  (I.  <?.,  separated 
from  the  blood)  partly  by 
the  mucous  membrane 

which   lines   the    mouth, 
FIG.  24.— STRUCTURE  OF  A  SALIVARY  GLAND.  ,          ,  .    „     ,        ,  ,. 

but  chiefly  by  the  salivary 

glands,  of  which  there  are  three  pairs  situated  near  the  mouth. 

15.  These  glands  consist  of  clusters  of  very  small  pouches,  arounc] 
which  a  delicate  network  of  blood-vessels  is  arranged ;  they  empty 
into  the  mouth  by  means  of  little  tubes,  or  ducts.     The  flow  fronj 
these  glands  is  generally  sufficient  to  maintain  a  soft  and  moist 
condition  of  the  tongue  and  mouth ;  but  when  they  are  excited  by 

teeth  are  changed  by  decomposition  into  lactic  acid.  Occasional  examination 
of  the  teeth  is  prudent,  in  order  that  a  commencing  cavity  may  be  promptly 
detected  and  remedied.  Teeth  that  are  decayed  beyond  remedy  by  filling 
should  be  immediately  removed."— Lane  on  the  Hygiene  of  the  Teeth. 


13.  Destruction  of  the  enamel  1    How  guarded  against  t 

14.  Mixing  of  food  with  the  saliva  ?    What  is  the  saliva?    How  secreted?    The  salivary 
glands? 

15.  The  flow  of  saliva?    The  thought  of  food?    Anxiety  and  grief?    Animals  fed  upon 
dry  and  coarse  food  ? 


DIGESTION. 

the  presence  and  taste  of  food,  they  pour  forth  the 
freely.  Even-  the  mere  thought  of  food  will  at  times 
saliva  to  flow,  as  when  the  ap- 
petite is  stimulated  by  the  sight 
or  smell  of  some  savory  article ; 
so  that  the  common  expression 
is  correct  that  "  the  mouth  wa- 
ters "  for  the  favorite  articles  of 
food.  Anxiety  and  grief  pre- 
vent its  flow,  and  cause  "the 
tongue  to  cleave  to  the  roof  of 
the  mouth."  In  the  horse,  and 
other  animals  that  feed  upon 
dry  and  coarse  fodder,  and  re-  FIG.  25.-THE  HEAD  OF  A  HORSE,  showing  the 

rmi'rn      in      almnrlanf     cnTYrVhr     nf      large  salivary  gland  (a),  its  duct  (&),  the  nms- 
naant    Supply    <          cle°  Qf  mastication  (C>  d,  e,  /,  and  g). 

saliva,    we    find    large    salivary 

glands,  as  well  as  powerful  muscles  of  mastication. 

\I6.  The  mingling  of  the  saliva  with  the  food  seems  a  simple 

process,  but  it  is  one  that  plays  an  important  part  in  digestion.  In 
the  first  place,  it  facilitates  the  motions  of  mastication,  by  moisten- 
ing the  food  and  lubricating  the  various  organs  of  the  mouth. 
Secondly,  it  prepares  the  way  for  other  digestive  acts :  by  the  action 
of  the  teeth,  the  saliva  is  forced  into  the  solid  food,  softens  the 
harder  substances,  and  assists  in  converting  the  whole  morsel  into 
a  semi-solid,  pulpy  mass,  that  can  be  easily  swallowed,  and  readily 
acted  upon  by  other  digestive  fluids.  The  saliva,  also,  by  dissolv- 
ing certain  substances,  as  sugar  and  salt,  develops  the  peculiar  taste 
of  each  ;  whereas,  if  the  tongue  be  dried  and  coated,  they  are  taste- 
less. Hence,  if  substances  are  insoluble,  they  are  devoid  of  taste. 

17.  Finally,  the  saliva  has  the  property  of  acting  chemically  upon 
the  food.  As  we  have  before  stated  (Chap.  IV.),  starch,  as  starch, 
cannot  enter  the  tissues  of  the  body ;  but,  in  order  to  become  nutri- 
ment, must  first  be  changed  to  grape-sugar.  This^  change  is,  in 
part,  effected  by  the  saliva,  and  takes  place  almost  instantly,  when* 
ever  it  comes  in  contact  with  cooked  starch.  This  important  funo 

16.  Importance  of  the  process?    The  first  place  ?    The  second?    The  third? 

17.  Its  final  importance ?    Starch?    How  effected?    Ptyalin? 


110 


DIGESTION. 


tion  is  due  to  an  organic  ingredient  of  the  saliva  called  ptyalin. 
This  substance  has  been  extracted  from  the  saliva  by  the  chemist, 
and  has  been  found,  by  experiment,  to  convert  into  sugar  two  thou- 
sand times  its  own  weight  of  starch.  (Read Note  2.)  (SeeApp.,p.  304.) 

18.  Importance  of  Mastication   and   Insalivation. — Each  of 
thgse  processes  complements  the  other,  and  makes  the  entire  work 
available ;  for,  by  their  joint  action,  they  prepare  the  food  in  the 
best  possible  manner  for  further  digestive  changes.     The  study  of 
these  preliminary  functions  will  appear  the  more  important,  when 
we  reflect  that  they  are  the  only  ones  which  we  can  regulate  by  the 
wilL     For,  as  soon  as  the  act  of  swallowing  begins,  the  food  not 
only  passes  out  of  sight,  but  beyond  control ;  and  the  subsequent 
acts  of  digestion  are  consequently  involuntary  and  unconsciously 
performed. 

19.  It  is  generally  known  that  rapid  eating  interferes  with  diges- 

2.  The  First  Step  of  Digestion. — "The  digestive  process  begins  in 
the  mouth  ;  among  civilized  people  it  begins  in  the  plate,  or  even  before. 
Undoubtedly  mastication  is  the  natural  method  of  mincing  meat,  and  not  the 
least  of  its  value  lies  in  the  fact  that  it  takes  time.  A  man  who  is  eating  a 
tough,  and  therefore  not  very  digestible  chop,  will  be  slow  in  eating,  if  he  is 
careful  to  masticate  it  well.  There  will  be  a  long  interval  between  each 
mouthful,  and  the  stomach  will  run  no  risk  of  being  hastily  loaded. 

"Now,  a  hastily-loaded  stomach  is  as  bad  almost  as,  or  rather,  is  the  same 
thing  as,  an  overloaded  stomach ;  and  there  can  be  1.0  doubt  that  artificial 
mastication  becomes  a  snare  when  it  leads  any  one  to  introduce  a  large  quan- 
tity of  finely-minced  meat  suddenly  and  rapidly  into  an  unprepared  stomach, 
especially  into  the  feeble  stomach  of  an  invalid,  under  the  idea  that,  because 
the  meat  is  so  nicely  minced,  and  so  very  tender,  it  can  be  no  possible  burden 
to  that  sorely-tried  organ.  Natural  mastication  has,  besides,  another  advan- 
tage over  the  artificial  process,  which  is  perhaps  not  always  recognized. 
Whenever  food  enters  the  mouth,  it  gives  rise  to  what  is  called  a  flow  of  saliva. 
This  saliva  is  secreted  by  certain  glands,  which  pour  into  the  mouth  the  fluid 
they  strain  off  from  the  blood,  and  which  are  excited  or  stimulated  to  action 
by  the  presence  of  food  in  the  mouth,  as  well  as  by  other  causes.  Saliva  rap- 
idly changes  starch  into  sugar,  and  sugar  is  pre-eminently  a  soluble  body,  pass 
ing  with  the  greatest  ease  from  the  alimentary  canal  into  the  blood.  "—People's 
Magazine  (London). 

18.  Each  of  the  processes?    Why  is  a  knowledge  of  the  digestive  ftmctions  important! 
How  shown? 

19.  Rapid  eating?    Describe  the  process  and  effects. 


,, 


DIGESTION.  113 


tion.  How  does  this  occur  T  In  the  first  place,  in  rapid  eating,  the 
flow  of  the  saliva  is  insufficient  to  moisten  the  solid  parts  of  the 
food,  so  that  they  remain  too  hard  and  dry  to  be  easily  swallowed. 
This  leads  to  the  free  and  frequent  use  of  water,  or  some  other 
beverage,  at  meals,  to  "  wash  down  "  the  food — a  most  pernicious 
practice.  For  these  fluids  not  only  cannot  take  the  place  of  the 
natural  digestive  juices,  but,  on  the  contrary,  dilute  and  weaken 
them. 

20.  Secondly,  the  saliva  being  largely  the  medium  of  the  sense 
of  taste,  the  natural  flavors  of  the  food  are  not  developed,  and  con- 
sequently it  appears  comparatively  insipid.     Hence  the  desire  for 
highly-seasoned  food,  and  pungent  sauces,  that  both  deprave  the  taste 
and  over  excite  the  digestive  organs.     Rapid  eating  also  permits 
the  entrance  of  injurious  substances  which  may  escape  detection  by 
the  taste,  and  be  unconsciously  received  into  the  system.     In  some 
instances,  the  most  acrid  and  poisonous  substances  have  frequently 
been  swallowed  "  by  mistake,"  before  the  sense  of  taste  could  act, 
and  demand  their  rejection. 

21.  Thirdly,  the  food,  being  imperfectly  broken  up  by  the  teeth, 
is  hurried  onward  to  the  stomach,  to  be  by  it  more  thoroughly 
divided.     But  the  stomach  is  not  at  all  adapted  to  perform  the  task 
thus  imposed  upon  it;  and  the  crude  masses  of  food  remain  a  heavy 
burden  within  the  stomach,  and  a  source  of  distress  to  that  organ, 
retarding  the  performance  of  its  proper  duty.     Hence  persons  who 
habitually  eat  too  rapidly,  frequently  fall  victims  to  dyspepsia.* 
Rapid  eating  also  conduces  to  overeating.     The  food  is  introduced 
so  rapidly,  that  the  system  has  not  time  to  recognize  that  its  real 
wants  are  met,  and  hence  the  appetite  continues,  although  more 
nutriment  has  been  swallowed  than  the  system  requires,  or  can 
healthfully^appropriate. 

^'227  The  Stomach. — As  soon  as  each  separate  portion  of  food  is 
masticated  and  insalivated,  it  is  swallowed ;  that  is,  it  is  caused  to 
move  downward  to  the  stomach,  through  a  narrow  muscular  tube 

*  For  the  same  reason,  persons  who  prematurely  lose  their  teeth  suffer  from 
dyspepsia.   For  them  a  proper  means  of  relief  is  the  use  of  artificial  teeth. 


20.  Loss  of  taste  ?    Another  effect  of  rapid  eating  ?    Mistakes  rt 

'  ?    Dyspei 

Effects  of  gormandizing? 


*ev«    AJUW  «*•  uc*ow5  t      AMVIMW  ouwv  vi  la^iu.  cciuiujj,  ;       .lu 

21.  Effect  of  imperfectly-broken  food  in  the  stomach?    Dyspepsia?     Over-eating? 
82.  Gullet?    Describe  the  stomach  and  its  location.    F~    '      - 


114 


DIGESTION. 


about  nine  inches  in  length,  called  the  oesophagus,  or  gullet  (Fig.  27). 
The  stomach  is  the  only  large  expansion  of  the  digestive  canal,  and 
is  a  most  important  organ  of  digestion.  It  is  a  hollow,  pear-shaped 

pouch,  having  a  capacity  of 
three  pints,  in  the  adult. 
Its  walls  are  thin  and  yield 
ing,  and  may  become  unnat 
urally  distended,  as  in  the 
case  of  those  who  subsist 
on  a  bulky,  innutritious  diet, 
and  of  those  who  habitually 
gormandize. 

23.  The  stomach  has  also 
^two  openings;  that  by  which 
food  enters,  being  situated 
near  the  heart,  is  called  the 
cardiac,  or  heart  orifice;  the 
other  is  the  pylorus*  or 
"  gatekeeper,"  which  guards 
the  entrance  to  the  intes- 
tines, and,  under  ordinary 
circumstances,  permits  only 
such  matters  to  pass  it  as 
have  first  been  properly 
acted  upon  in  the  stomach. 
Coins,  buttons,  and  the  like 
are,  however,  readily  allowed 
to  pass,  because  they  can  be  of  no  use  if  retained.  The  soft  and 
yielding  texture  of  this  organ — the  stomach — indicates  that  it  is  not 
designed  to  crush  and  break  up  solid  articles  of  food. 

24.  The  Gastric  Juice. — We  have  seen  how  the  presence  of 
food  in  the  mouth  excites  the  salivary  glands,  causing  the  saliva 
quickly  to  flow.  In  the  same  manner,  when  food  reaches  the 
stomach,  its  inner  lining,  the  mucous  membrane,  is  at  once  excited 
to  activity.  At  first,  its  surface,  which  while  the  stomach  is  empty 

28.  Heart-orifice?  Gatekeeper?  Coins,  etc.  ?  Indication  of  the  soft  and  yielding  texture 
Of  the  stomach? 

24.  What  is  meant  by  the  gastric  juice? 


Fio.  26.— SECTION  OF  CHEST  AND  ABDOMEN. 


A,  Heart. 

B,  The  Lungs. 

C,  Diaphragm. 

D,  The  Liver. 


E,  Gall  Bladder. 

F,  Stomach. 

G,  Small  Intestine. 
H,  Large  Intestine. 


DIGESTION. 


115 


presents  a  pale  pink  hue,  turns  to  a  bright  red  color,  for  the  minute 

blood-vessels  which  course  through  it  are  filled  with  blood.     Pres- 

ently a  clear,  colorless,  and  acid  fluid  exudes,  drop  by  drop,  from 

millions  of   little  tubes  in   the   inner 

surface   of  the   stomach,  until  finally 

the  surface  is  moistened  in  every  part, 

and  the  fluid  begins  to  mingle  with  the 

food.     This  fluid  is  termed  the  gastric 

juice. 

25.  The  gastric  juice  dissolves  cer- 
tain articles  of  food,  especially  those 
belonging  to  the  albuminoid  class.   This 
solvent  power  is  due  to  its  peculiar  in- 
gredient, pepsin  ;  in  digestion,  this  sub- 
stance acts  like  a  ferment  —  that  is,  it 
induces  changes  in  the  food  simply  by 
its  presence,  but  does  not  itself  undergo 
change.    The  acidity  of  the  gastric  juice, 
which  is  due  to  hydrochloric  acid,  is  not 
accidental  ;  for  we  find  that  the  pepsin 
cannot  act  in  an  alkaline  solution  — 
that  is,  one  which  is  not  acid  or  neutral. 
The  quantity  of  gastric  juice  secreted 
daily  is  very  large,  probably  not  less 
than  three  or  four  pints  at  each  meaL 
Though  this  fluid  is  at  once  used  in 
the  digestion   of  the  food,  it  is  not 
lost;  since  it  is  soon   re-absorbed  by 
the  stomach,  together  with  those  parts 
of  the  food  which  it  has  digested  and 
holds  in  solution. 

26.  Movements  of  the  Stomach.  — 

_  FIG.  27.  ALIMENTARY  CANAL—  includ- 

The  inner  coating  of  the  stomach  is     lug  Gullet,  stomach,  Large  and 

, 

the  mucous  membrane,  which,  as  we 
have  seen,  furnishes  the  gastric  juice. 


Small  Intestines. 


Next  to  this  coating  lies 


25.  What  is  the  office  of  the  gastric  juice?    Acidity  of  the  gastric  juice?   Quantity  of 
gastric  juice  tased  ?    What  becomes  of  it  ? 

26.  Muscular  coat  of  the  stomach  ?   Expansion  and  contraction  of  its  fibres  I    Action  ol 
the  fibres  2 


116  DIGESTION. 

another,  called  the  muscular  coat,  composed  of  involuntary  musculai 
fibres,  some  of  which  run  circularly,  and  others  in  a  longitudinal 
direction.  These  expand  to  accomodate  the  food  as  it  is  introduced, 
and  contract  as  it  passes  out.  In  addition,  these  fibres  are  in  con- 
tinual  motion  while  food  remains  in  the  stomach,  and  they  act  in 
such  manner  that  the  contents  are  gently  turned  round  from  side 
to  side,  or  from  one  end  of  it  to  the  other. 

27.  By  these  incessant  movements  of  the  stomach,  called  the 
peristaltic  movements,  the  gastric  juice  comes  in  contact  with  all 
parts  of  the  food.      We  are,  however,  not  conscious  that  these 
movements  take  place,  nor  have  we  the  power  to  control  them. 
When  such  portions  of  the  food  as  are  sufficiently  digested  approach 
the  pylorus,  it  expands  to  allow  them  to  pass  out,  and  it  closes 
again  to  confine  the  residue  for  further  preparation. 

28.  The  knowledge  of  these  and  other  interesting  and  instruc- 
tive facts  has  been  obtained  by  actual  observation;  the  workings  of 
the  stomach  of  a  living  human  being  have  been  laid  open  to  view 
and  examined — the  result  of  a  remarkable  accident.     Alexis  St. 
Martin,  a  Canadian  voyageur,  received  a  gun-shot  wound  which  laid 
open  his  stomach,  and  which,  in  healing,  left  a  permanent  orifice 
nearly  an  inch  in  diameter.     Through  this  opening  the  observer 
could  watch  the  progress  of  digestion,  and  experiment  with  different 
articles  of  food.     Since  that  occurrence,  artificial  openings  into  the 
stomach  of  the  inferior  animals  have  been  repeatedly  made,  so  that 
the  facts  of  stomach-digestion  are  very  well  ascertained  and  verified. 
(Read  Note  3. ) 

29.  Gastric  Digestion. — What  portions  of  the  food  are  digested 
in  the  stomach  ?    It  was  formerly  thought  that  all  the  great  changes 
of  digestion  were  wrought  here,  but  later  investigation  has  taught 
us  better.     We  now  know  that  the  first  change  in  digestion  takes 

3.  The  Digestibility  of  Solid  Foods.— "The  accompanying  table 
shows  some  of  the  results  obtained  from  the  experiments  of  Dr.  Beaumont 
upon  the  stomach  of  Alexis  St.  Martin.  It  will  surprise  many  to  find  that 


27.  Peristaltic  movements?    What  is  said  of  our  consciousness  of  and  power  over  these 
movements  ?    Describe  the  movement  of  the  pylorus. 

28.  How  has  the  knowledge  and  the  workings  of  the  stomach  been  ascertained?    St. 
Martin  ?    How  else  ? 

29.  What  was  formerly  thought?    What  do  we  now  know?    What  else  do  we  now  know? 
Water,  salt,  and  sugar?    Absorption  ? 


DIGESTION. 


117 


place  in  the  mouth,  by  the  partial  conversion  of  starch  into  sugar. 
We  also  know  that,  of  the  three  organic  food  principles  (considered 
in  Chapter  IY.)  two — the  fats  and  the  sugars — are  but  slightly 
affected  by  the  stomach;  but  that  its  action  is  confined  to  that  third 
and  very  important  class  from  which  the  flesh  is  formed,  the  albu 
minoids.  A  few  articles  need  no  preparation  before  entering  the 
system,  as  water,  salt,  and  fruit-sugar.  These  are  rapidly  taken  up 
by  the  blood-vessels  of  the  stomach,  which  everywhere  underlie  its 
mucous  membrane  in  an  intricate  and  most  delicate  network.  In 
this  way  the  function  of  absorption  begins. 

30.  The  albuminoid  substances  are  speedily  attacked  and  digested 
by  the  gastric  juice.  From  whatever  source  they  are  derived,  vege- 
table or  animal,  they  are  all  transformed  into  the  same  digestive 
product,  called  albuminose.  This  is  very  soluble  in  water,  and  is 
in  part  absorbed  by  the  blood-vessels  of  the  stomach.  After  a 
longer  or  shorter  time,  varying  from  one  to  five  hours,  according  to 
the  individual  and  the  quantity  and  quality  of  his  food,  the  stomach 
will  be  found  empty.  Not  only  the  unabsorbed  digested  food,  but 
also  those  substances  which  the  stomach  could  not  digest,  have 

vegetable  foods — they  are  placed  in  the  latter  part  of  the  table — require  so  long 
a  time  for  their  digestion. 


Food. 

Pork... 

Time  re- 
Mode  of       quired  for 
Cooking.      digestion. 
b.  m. 

.  .roasted  5  15 

Salmon  Trout  .... 

Mode  of 
Cooking. 

...  boiled 

Time  re- 
quired  for 
digestion, 
h.  m. 

1  30 

Cartilage       

boiled     4  15 

Eggs  (whipped) 

raw 

1  30 

Ducks  

....roasted  4    0 

Tripe  (soused)..'" 

..  boiled 

.     1    0 

Fowls  
Do.    . 

....    do  4    0 
boiled  4    0 

Pig's  Feet  (soused).  .  . 
Cabbage 

....do.     . 
boiled 

1    0 

4    o 

Beef  

...  fried  4    0 

Beetroot  \  . 

do.    .. 

.  .  .  .  3  45 

Eggs 

do  3  30 

Turnips 

do 

3  30 

Do  

....hard  boiled..  3  30 

Potatoes  

.    do. 

3  30 

Cheese          

3  30 

Wheaten  Bread 

baked 

3  30 

Oysters  
Mutton      

....stewed  3  30 
roasted  ...    3  15 

Carrot  

Indian  Corn  Bread 

....boiled., 
baked 

...3  15 
3  15 

Do  
Beef.  

...boiled  3    0 
....roasted  3    0 

Do.        Cake  .  .  . 
Apple-dumpling  

....    do.    .. 
boiled 

...   .3    0 
.  3    0 

Do  

Chicken    

....boiled  2  45 
..  fricasseed  .    2  45 

Potatoes  
Do 

....baked.. 

2  33 

2  30 

Lamb  

Pig  (suckling)  

....broiled  2  30 
.  .  .  .roasted  •        2  30 

Parsnips  

Sponge  Cake 

....boiled., 
baked 

2  30 

2  30 

Goose  ... 

do                2  30 

boiled 

2  30 

Gelatin  

....boiled  2  30 

Apples  (sour)  

.   ...2    0 

Turkey  
Eggs....  

...    do  2  25 

..  .roasted           2  15 

Barley  

Tapioca 

....boiled.. 
.     do.     . 

2    0 
..      20 

Cod  Fish  (cured,  dry). 

....boiled  2    0 

....    do.    .. 

1  45 

Ox  Liver  
Venison  Steak  

....broiled  2    0 
....    do  1  30 

Apples  (sweet)  
Rice  

....raw.... 
....boiled.. 

1  80 
1    0 

30.  Albuminose?    The  process?    Chyme? 


118  DIGESTION. 

passed  little  by  little  through  the  pylorus,  to  undergo  further  action 
in  the  intestines.  At  the  time  of  its  exit  the  digested  food  is  of  a 
pulpy  consistence,  and  dark  color,  and  is  then  known  as  the  chyme. 
(Read  Note  4. )  (See  Appendix,  page  304 .) 

31.  The  Intestines. — The   intestines  are   continuous  with   the 
stomach,  and  consist  of  a  fleshy  tube,  or  canal,  twenty-five  feet  in 
length.     The  small  intestine,  whose  diameter  is  about  one  inch 
and  a  half,  is  twenty  feet  long,  and  very  winding.     The  large  in- 
testine is  much  wider  than  the  former,  and  five  feet  long  (Fig.  27). 
The  general  structure  of  these  organs  resembles  that  of  the  stomach. 
Like  it,  they  are  provided  with  a  mucous  membrane,  or  inner  lin- 
ing, whence  flow  their  digestive  juices ;  and,  just  outside  of  this, 
a  muscular  coat,  which  propels  the  food  onward  from  one  point,  to 
another. 

32.  Moreover,  both  the  intestines  and  stomach  are  enveloped  in 
the  folds  of  the  same  outer  tunic  or  membrane,  called  the  peri- 
toneum.    This  is  so  smooth  and  so  well  lubricated,  that  the  intes- 
tines have  the  utmost  freedom  of  motion  within  the  abdomen.     In 
the  small  intestines  the  work  of  digestion  is  completed,  the  large 
intestine  receiving  from  them  the  indigestible  residue  of  the  food, 
and  in  time  expelling  it  from  the  body. 

33.  Intestinal   Digestion. — As  soon  as  the   food    passes    the 
pylorus  and  begins  to  accumulate  in  the  upper  part  of  the  intes- 
tines, it  excites  the  flow  of  a  new  digestive  fluid,  which  enters 
through  a  small  tube,  or  duct,  about  three  inches  below  the  stom- 
ach.    It  is  formed  by  the  union  of  two  distinct  fluids — the  bile  and 
the  pancreatic  juice.     The  bile  is  secreted  by  the  cells  of  the  liver, 

4.  Indigestible  Matters. — "Children  sometimes  swallow  coins ,  but- 
tons, etc.,  and  so  cause  great  alarm.  There  is  little  real  ground  for  apprehen- 
sion under  these  circumstances,  unless  the  coins  are  bronze.  If  the  latter, 
there  is  some  cause  for  fear  that  copper  poisoning  will  ensue,  and  the  ready 
passage  of  the  coin  is  desirable.  This  is  best  effected  by  meals  of  figs  or  pud- 
ding, in  which  the  coins  are  imbedded,  and  so  passed  harmlessly.  As  to  bulk, 
whatever  will  go  into  the  stomach  will  pass  the  various  straits  and  emerge 
again. " — Fothergill. 

31.  What  are  the  intestines?     The  small  intestines?     The   large    intestines?     Thei* 
gtructure? 

32.  Peritoneum?    The  work  of  digestion? 

83.  The  presence  of  food  in  the  intestines  ?    Bile  ? 


DIGESTION.  119 

the"  largest  gland  of  the  body,  situated  on  the  right  side  and  upper 
part  of  the  abdomen  (Fig.  26).  The  bile  is  constantly  formed,  but  it 
flows  most  rapidly  during  digestion.  During  the  intervals  of  diges- 
tion it  is  stored  in  the  gall-bladder,  a  small  membranous  bag  attached 
to  the  under  side  of  the  liver.  This  fluid  is  of  a  greenish-yellow  color, 
having  a  peculiar  smell,  and  a  very  bitter  taste.  (See  Appendix,  p.  305.) 

34.  The  pancreatic  juice  is  the  product  of  a  gland  called  the 
pancreas,  situated  behind  the  stomach.      This  fluid  is  colorless, 
viscid,  alkaline,  and  without,  odor.     Like  the  digestive  juices  pre- 
viously described,  it  owes  its  solvent  power  to  its  peculiar  ferments. 
The  most  important  of  these  ferments,  called  pancreatin,  transforms 
starch  into  sugar.     Another,  trypsin,  causes  the  solution  of  undis- 
solved  albuminoid  substances ;  and  a  third  ferment,  which  has  not 
received  a  name,  causes  a  partial  acidification  of  the  fats.     By  the 
joint  action  of  these  fluids,  the  food  is  prepared  for  absorption. 
There  results  from  this  action  of  the  pancreatic  juice  a  white  and 
milky  fluid,  termed  the  chyle,  which  holds  in  solution  the  digestible 
portions  of  the  food,  and  is  spread  over  the  extensive  absorbent 
surface  of  the  small  intestines.    (See  Appendix,  page  305.) 

35.  The  mucous  membrane  of  the  intestines,  also,  secretes  cr 
produces  a  digestive  fluid  by  means  of  numerous  "follicles,"  cr 
minute  glands ;   this  is  called  the  intestinal  juice.     From  experi- 
ments on  the  lower  animals,  it  has  been  ascertained  that  this  fluid 
exerts  a  solvent  influence  over  each  of  the  three  organic  food  prin- 
ciples, and  in  this  way  completes  the  action  of  the  fluids  previously 
mentioned,  viz.: — of  the  saliva  in  converting  starch  into  sugar,  of 
the  gastric  juice  in  digesting  the  albuminoids,  and  of  the  pancreatic 
juice  and  bile  in  emulsifying  the  fats. 

36.  Absorption. — With  the  preparation  of  the  chyle,  the  work  of 
digestion  is  completed;  but  it  has  not  yet  become  a  part  of  the 
blood,  by  means  of  which  it  is  to  reach  the  different  parts  of  the 
body.     The  process  by  which  the  liquefied  food  passes  out  of  the 
alimentary  canal   into   the   blood   is   called  absorption.      This  is 
accomplished  in  two  ways;    first,  by  the  blood-vessels.     We  have 


84.  The  pancreatic  juice  ?    The  joint  action  of  these  fluids? 

85.  The  mucous  membrane  ?    Experiments  on  inferior  animals? 
8<).  How  much  thus  far  has  been  done  with  the  food  if 


120 


DIGESTION. 


seen  how  the  inner  membrane  of  the  stomach  is  underlaid  by  a 
tracery  of  minute  and  numerous  vessels,  and  how  some  portions  of 
the  food  are  by  them  absorbed.  The  supply  of  blood-vessels  to  the 
intestines  is  even  greater;  particularly  to  the  small  intestines,  where 
the  work  of  absorption  is  most  actively  carried  on. 

37.  The  absorbing  surface  of  the  small  intestines,  if  considered 
as  a  plane  surface,  amounts  to  not  less  than  half  a  square  yard. 
Besides,  the  mucous  membrane  is  formed  infolds  with  an  immense 
number  of  thread-like  prolongations,  called  villi,  which  indefinitely 
multiply  its  absorbing  capacity.  These  villi  give  the  surface  the 
appearance  and  smoothness  of  velvet,  and  during  digestion  they  dip 

into  the  canal,  and,  by  means 
of  their  blood-vessels,  absorb 
its  fluid  contents,  just  as  the 
spongioles  which  terminate 
the  rootlets  of  plants,  imbibe 
moisture  from  the  surround- 
ing soil. 

38.    Secondly,   absorption 
is  also    effected   by  the   lac- 
a  set  of  vessels  pecu- 


liar to  the  small  intestines. 
A  These  have  their  beginnings 
in  the  little  villi  just  men- 
tioned, side  by  side  with  the 
blood-vessels.   These  two  sets 
of  absorbents  run  in  different 
courses,  but  their  destination 
is  the   same,   which   is   the 
right  side  of  the  heart.     The 
lacteals   receive   their    name 
from   their  milky-white    ap- 
pearance.    After  a  meal  containing  a  portion  of  fat,  they  are  dis- 
tended with  chyle,  which  they  are  specially  adapted  to  receive ;  at 
other  times  they  are  hardly  discernible.     The  lacteals  all  unite  to 


B 


Fio.  28.— THE  LACTEALS. 
A,  Small  Intestine.        B,  Lacteals. 
C,  Thoracic  Duct.         D,  Absorbents. 
E,  Blood-  vessel. 


87.  The  next  process?    Give  the  first  way? 

88.  How  is  absorption  effected  in  another  way?    Describe  it 
Thoracic  duet? 


Name  of  the  lacteals; 


WGE8TION.  121 

form  one  tube,  the  thoracic  duct,  which  passes  upward  through  the 
thorax,  or  chest,  and  empties  into  a  large  vein,  situated  just  beneath 
the  left  collar-bone. 

39.  The  Absorbents. — The  lacteals  belong  to  a  class  of  vessels 
known  as  absorbents,  or  lymphatics,  which  exist  in  nearly  all  parts 
of  the  body,  except  the  brain  and  spinal  cord.     The  fluid  which 
circulates  through  the  lymphatics  of  the  limbs,  and  all  the  organs 
not  concerned  in  digestion,  is  called  lymph.     This  fluid  is  clear  and 
colorless,  like  water,  arid  thus  differs  from  the  milky  chyle  which 
the  lacteals  carry  after  digestion :  it  consists  chiefly  of  the  watery 
part  of  the  blood,  which  was  not  required  by  the  tissues,  and  is 
returned  to  the  blood  by  the  absorbents  or  lymphatics.  (Read  Note  5.) 

40.  Circumstances  Affecting    Digestion. — What  length  of 
time  is  required  for  the  digestion  of  food?     From  observations 
made,  in  the  case  of  St.  Martin,  the  Canadian  already  referred  to, 
it  has  been  ascertained  that,  at  the  end  of  two  hours  after  a  meal, 

5.  Absorption  cf  the  Lacteals.— "The  force  by  which  the  milky  fluid 
moves  upward  through  the  lacteals  is  very  considerable.  This  has  been 
proved  by  the  distension  of  the  whole  system  of  vessels,  including  the  thoracic 
duct,  even  to  the  occurrence  of  rupture,  when  that  duct  has  been  tied  in  an 
animal  a  short  time  before  it  has  been  fed.  The  movement  of  the  fluid  thus, 
in  some  measure,  resembles  absorption  by  the  spongioles  at  the  extremities  of 
the  roots  of  trees,  and  the  continuous  rising  of  the  sap.  The  thoracic  duct 
may  become  diseased,  and  a  serious  derangement  of  nutrition  take  place. 
In  the  case  of  an  unfortunate  person,  who  was  some  years  ago  exhibited  as  a 
curiosity  under  the  name  of  the  'living  skeleton,'  was  illustrated  the  slow 
starvation  that  may  thus  be  produced.  Although  he  was  able  to  take  food  in 
abundant  supply,  he  was  not  nourished  by  it.  Finally  he  died,  and  an  exami- 
nation of  his  body  disclosed  the  fact  that  the  thoracic  duct  had  been  obstructed 
by  disease,  and  absorption  by  the  lacteals  was  prevented.  Hard  work  directly 
after  a  hearty  meal  is  bad  practice.  Remember  the  story  of  the  two  hounds. 
They  were  both  fed  alike  in  the  morning  ;  one  of  them  was  taken  out  to  run 
on  a  hunt,  the  other  was  tied  up  at  home.  When  the  master  came  back  from 
the  hunt,  both  dogs  were  killed,  and  tbeir  stomachs  examined.  It  was  found 
that  the  hound  that  hunted  still  had  the  stomach  full  of  food,  while  that  of 
the  stay-at-home  was  empty.  When  you  have  a  hard  piece  of  work  on  hand, 
do  not  eat  much  ;  the  more  you  eat  the  weaker  you  are  for  the  purpose. - 
Buckland  (in  part}. 


39.  The  absorbents  ?    Lymph  ?    What  further  of  the  lymph  ? 

40.  What  can  you  state  as  to  the  time  required  for  digestion  ? 


122  DIGESTION. 

the  stomach  is  ordinarily  empty.  How  much  time  is  needed  to 
complete  the  digestion  of  food,  within  the  small  intestines,  is  not 
certain ;  but,  from  what  we  have  learned  respecting  their  methods 
of  action,  it  must  be  evident  that  it  largely  depends  upon  the 
amount  of  starch  and  fat  which  the  food  contains. 

41.  In  addition  to  the  preparation  which  the  food  undergoes  in 
cooking,  which  we  have  already  considered,  many  circumstances 
affect  the  duration  of  digestion ;  such  as  the  quality,  quantity,  and 
temperature  of  the  food ;  the  condition  of  the  mind  and  body ; 
sleep,  exercise,  and  habit.     Fresh  food,  except  new  bread  and  the 
flesh  of  animals  recently  slain,  is  more  rapidly  digested  than  that 
which  is  stale ;  and  animal  food  more  rapidly  than  that  from  the 
vegetable  kingdom. 

42.  Food  should  not  be  taken  in  too  concentrated  a  form,  the 
action  of  the  stomach  being  favored  when  it  is  somewhat  bulky ; 
but  a  large  quantity  in  the  stomach,  especially  if  there  is  mucn 
liquid,  often  retards  digestion.     If  the  white  of  one  egg  be  given 
to  a  dog,  it  will  be  digested  in  an  hour,  but  if  the  white  of  eight 
eggs  be  given  it  will  not  disappear  in  four  hours.   '  A  wine-glassful 
of  ice-water  causes  the  temperature  of  the  stomach  to  fall  thirty 
degrees ;  and  it  requires  a  half-hour  before  it  will  recover  its  natural 
warmth — about  a  hundred   degrees-t-at  which  the  operations  of 
digestion  are  best  conducted.     A  variety  of  articles,  if  not  too  large 
in  amount,  is  more  easily  disposed  ol  than  a  meal  made  of  a  single 
article;  although  a  single  indigestible  article  may  interfere  with 
the  reduction  of  articles  that  are  easily  digested.     {Read  Note  6. ) 

6.  Digestibility  of  Warm  Food.— "It  is  very  desirable  that  all  cooked 
food  should  be  taken  hot.  When  it  is  eaten  cold  it  reduces  the  temperature 
of  the  stomach,  and  both  the  nerves  and  vessels  of  the  stomach  are  taxed  in 
order  to  bring  the  temperature  of  the  food  thus  taken  up  to  that  of  the  human 
body.  Mankind  in  all  ages  seems  to  have  discovered  that  it  is  desirable  to  pre- 
vent this  tax  upon  the  internal  organs,  and  have  taken  their  food  hot  in  order 
to  prevent  it  It  was  death  to  the  Roman  slave  to  bring  in  his  master's  water 
tepid  or  cold — so  much  importance  did  they  attach  to  hot  water  as  drink." 
Many  of  our  own  beverages  are  taken  hot  even  in  summer  weather  ;  and  it 
is  an  economy  of  the  vital  powers  to  take  hot  meals  rather  than  cold  ones. 

41.  Circumstances  affecting  duration  of  digestion  ?    Fresh  food  ? 

42.  Food  in  concentrated  form?    A  large  quantity  of  food  it    Experiment  on  the  dog? 
Ice- water?    Variety  of  articles? 


YJ_,  BBWIIOT.  123 

43.  Strong  emotion,  whether  of  excitement  or  depression,  checks 
digestion,  as  do  also  a  bad  temper,  anxiety,  business  cares,  and 
bodily  fatigue.     The  majority  of  these  conditions  make  the  mouth 
dry — that  is,  they  restrain  the  flow  of  the  saliva;  and  without 
doubt  they  render  the  stomach  dry  also,  by  preventing  the  flow 
of  the  gastric  juice.     And,  as  a  general  rule,  we  may  decide,  frou 
a  parched  and  coated  tongue,  that  the  condition  of  the  stomach  is 
not  very  dissimilar,  and  that  it  is  unfit  for  the  performance  of 
digestive  labor.     This  is  one  of  the  points  which  the  physician 
bears  in  mind  when  he  examines  the  tongue  of  his  patient.     (Read 
Note-].} 

44.  The  practice  of  eating  at  short  intervals,  or  "  between  meals," 
as  it  is  called,  has  its  disadvantage,  as  well  as  rapid  eating  and 
over-eating,  since  it  robs  the  stomach  of  its  needed  period  of  entire 
rest,  and  thus  overtasks  its  power.     With  the  exception  of  infants 
and  the  sick,  no  persons  require  food  more  frequently  than  once  in 
four  hours.     Severe  exercise,  either  directly  before  or  directly  after 
eating,  retards  digestion ;  a  period  of  repose  is  most  favorable  to 
the  proper  action  of  the  stomach.     The  natural  inclination  to  rest 
after  a  hearty  meal  may  be  indulged,  but  it  should  not  be  carried 
to  the  extent  of  sleeping ;  since  in  that  state  the  stomach,  as  well 
as  the  brain  and  the  muscles,  seeks  release  from  labor.    {Read  Notes 
8  and  g. ) 

As  a  rule,  hot  food  is  better  than  cold,  in  our  climate,  except  in  very  hot 
weather ;  in  tropical  climates  only  can  food  be  taken  with  advantage  when 
cold,  or  ice  and  iced  drinks  be  used  with  impunity. " — Lankester's  Manual  of 
Health. 

7.  On  the  Demands  of  Digestion. — "The  system  never  does  two  things 
well  at  the  same  time.  No  one  can  meditate  a  poem  and  drive  a  saw  simulta- 
.  neously  without  dividing  his  force  ;  he  may  poetize  fairly  and  saw  poorly  ;  or 
he  may  saw  fairly  and  poetize  poorly  ;  or  he  may  both  saw  and  poetize  indif- 
ferently. Brain- work  and  stomach- work  interfere  with  each  other  if  attempted 
together.  The  digestion  of  i  dinner  calls  force  to  the  stomach,  and  tempo- 
rarily slows  the  brain  :  the  experiment  of  trying  to  digest  a  hearty  supper,  and 
to  sleep  during  the  process,  has  sometimes  cost  the  careless  experimenter  his 
life.  The  physiological  principle  is  to  do  only  one  thing  at  a  time,  if  you 
would  do  it  well." — Dr.  E.  H.  Clarke:  Sex  in  Education. 

Q.  Work  or  Exertion. — "The  best  time  to  make  great  exertion  is  about 

43.  Strong  emotion  ?    The  tongue  of  the  patient  ? 

44.  Eating  between  meals?    Severe  exercise?    Sleep  after  meals? 


124 


DIGESTION. 


45.  The  Kidneys. — Besides  those  already  described,  the  abdominal 
cavity  contains  other  important  organs,  viz.,  the  kidneys  and  spleen. 

two  hours  after  a  meal  It  is  not  a  good 
time  before  breakfast,  although  moderate  work 
may  be  then  performed  ;  and  those  who  go 
to  work  before  breakfast  should  first  take  a 
cup  of  hot  milk,  tea,  or  coffee,  or  other  sim- 
ple food.  The  body  is  weakest  before  breakfast. 
"Violent  or  rapid  exertion  made  by  chil- 
dren, and  also  by  stout  and  aged  people,  often 
injures,  and  sometimes  causes  disease  of  the 
heart,  when  the  same  taken  in  the  ordinary 
way  would  do  no  harm.  Rapidly  running 
up  stairs,  or  to  meet  a  train,  sometimes  causes 
death.  Hence,  while  exercise  is  of  the  utmost 
importance  to  health,  it  should  be  taken  in 
a  regulated  and  rational  manner,  and  particu- 
larly by  those  who  have  passed  the  period 
of  youth.  But  disease  of  the  heart,  even  in 
youth,  may  often  be  traced  to  indiscretion  in 
Fio.29. -THE  KIDNEYS  AND  BUDDER.  this  particular,  whether  in  rowing,  running, 

or  jumping. " — Edward  Smith  on  Health. 

9.  Tight  Clothing  interferes  with  Digestion.— "On  one  wet  win- 
ter's day  at  Florence,  some  years  ago,  I  had  been  spending  the  morning  in  the 
studio  of  a  sculptor  of  world- wide  reputation.  We  had  discussed  the  perfec- 
tions of  female  beauty,  and  I  felt  that  I  was  sitting  at  the  feet  of  a  thinker, 
9&  well  as  an  •  elegans  formarum  spectator.'  In  the  evening  we  met  again  at  a 
hospitable  palazzo,  and,  under  cover  of  the  waltz,  from  a  quiet  corner  of  obser- 
vation, we  saw  whirling  by  in  the  flesh,  much  that  we  had  been  thinking  of 
in  the  marble  and  the  clay,  and  our  eyes  could  not  but  follow  one  particular 
face,  famous  for  the  assistance  its  great  natural  beauty  received  from  art. 
4  Face,'  I  said,  but  the  mind  of  Hiram  Powers  was  penetrating  deeper,  for  he 
exclaimed,  after  a  short  silence  :  *  That  is  all  very  well,  but  I  want  to  know 
where  Lady puts  her  liver  !  *  Where,  indeed  !  for,  calculating  the  circum- 
ference of  the  waist  by  the  eye,  allowing  a  minimum  thickness  for  the  walls  of 
the  chest,  an  area  for  the  spine,  resophagus,  and  great  blood-vessels,  the  sec- 
tion of  the  waist  seemed  to  admit  of  no  room  for  anything  else.  In  such  a 
body  the  liver  must  be  squeezed  down  into  the  abdomen,  stick  into  its  hollow 
neighbors,  and  infringe  upon  all  the  organs.  The  organ  which  suffers  most  is 
the  unresisting  stomach,  which  is  dragged  and  pushad  out  of  all  form  during 
the  continuance  of  this  packing  process." — Dr.  T.  K.  Chambers  on  the  Indi- 
gestions*   

45.  What  are  the  kidneys  and  their  functions  ? 


DIGESTION.  125 

The  kidneys  are  two  in  number,  located  in  the  loins  behind  the 
intestines,  one  on  each  side  of  the  spinal  column.  They  are 
shaped  like  a  bean,  being  about  four  inches  long,  two  inches 
wide,  and  one  inch  thick.  The  function  of  the  kidneys  is  to 
purify  the  blood  by  removing  from  it  a  poisonous  substance  called 
urea  and  certain  waste  products.  If  their  action  is  in  any  way 
interfered  with,  blood-poisoning  takes  place,  on  account  of  the 
accumulation  of  urea,  and  effete  materials  in  the  system,  producing 
coma,  which  rapidly  proves  fatal  unless  it  is  relieved.  The  watery 
fluid  secreted  by  the  kidneys  is  carried  by  two  tubes,  called  ureters, 
to  the  bladder. 

46.  The  Spleen. — The  spleen  is  situated  on  the  left  side  of  the 
abdomen  behind  the  stomach.      It  is  called  the  "milt"  by  the 
butcher.     It  has  no  duct,  and  its  uses  are  not  positively  known. 
In  malarial  fevers,  it  is  sometimes  much  enlarged,  and  the  individual 
is  said  to  have  an  "ague  cake.' 

47.  Effect  of  Alcohol  upon  Digestion.— "The  irritating  effects 
ol  alcohol  upon  the  lining  of  the  stomach  *  are  first  seen  in  deranged 
digestive  action,  in  loss  of  appetite,  and  at  a  later  stage,  in  changes 
in  the  stomach's  structure,  principally  by  a  thickening  of  the  walla 
of  that  organ.     (React  Note  10.) 

*  Dyspepsia  due  to  Alcohol — "Many  cases  of  dyspepsia  are  due  to 
alcohol  solely  and  wholly,  and  no  reliance  whatever  can  be  placed  upon  the 
word,  statement,  or  assertion  under  oath  of  a  drunkard  ;  for  '  a  drunkard  13 
a  liar.'  And  this  holds  good  of  both  sexes,  all  ages,  everywhere  and  ever." — 
Dr.  J.  M.  Fothergill 

10.  Cordials,  Bitters, etc. — "In  health,  alcohol  no  wise  plays  a  friendly 
part  in  regard  to  digestion.  And  it  is  just  here  that  a  mistake  is  made  by 
many  persons  who  have  been  deluded  into  the  use  of  what  are  termed  '  cor- 
dials'  ;  these  are  very  strong  alcoholic  liquors,  and  they  are  supposed  by  those 
who  use  them  to  be  especially  appropriate  at  the  end  of  a  hearty  meaL  Ab- 
sinthe, the  pet  poison  of  the  Parisian,  is  one  of  these  falseiy-named  'cordial' 
substances.  These  cordials  are  never  less  welcome  than  after  a  substantial 
meal.  So  many  misleading  names  have  been  given  to  beverages  (Cordials, 
Bitters,  etc. ),  that  many  persons  have  used  them  without  knowing  the  evil 
consequences  which  follow.  It  is  made  clear  by  recent  proofs  that  the  so- 
called  cordials  are  the  most  rapidly  poisonous  of  all  the  spirituous  beverages." 

46.  What  is  the  location  of  the  spleen? 

47.  How  is  the  digestion  affected  by  alcohol  ¥ 


126  DIGESTION. 

Dr.  Beaumont  was  able  to  observe  the  condition  of  the  stom 
ach  of  Alexis  St.  Martin  (see  paragraph  28,  page  116)  after  alcoholic 
excesses.  He  states  that  the  surface  of  the  organ  was  overcharged 
with  blood,  at  times  drops  of  blood  exuding  from  it ;  and  that  ita 
secretions  became  thick,  unnatural,  and  slightly  tinged  with  blood.* 
It  is  a  fact  beyond  dispute  that  other  organs  concerned  in  the  act 
of  digestion,  particularly  the  liver,  become  diseased  by  the  habitual 
use  of  spirituous  liquors,  (Read Note  n.) 

48.  Effects  of  Alcohol  on  the  Liver. — When  alcohol  is  taken 
into  the  stomach  it  is  absorbed,  and  is  carried  by  the  portal  vein 
directly  into  the  liver.  The  blood  in  the  liver  is  th#s  made  more 
stimulating,  and  repeated  stimulation  produces  over-action,  which 
results  in  impairment  or  loss  of  power  to  secrete  healthy  bile.  For 
the  same  reason,  organic  changes  take  place  more  frequently  in  the 
liver,  from  the  use  of  alcohol,  than  in  any  other  organ.  It  first 
becomes  enlarged,  owing  to  congestion  from  obstruction  of  the  circu- 
lation and  excessive  growth  of  the  connective  tissue.  One  result 
of  this  overgrowth  is  compression  and  diminution  in  size  of 
the  cells  which  secrete  the  bile.  Another  result  is  a  hindrance 
to  the  flow  of  blood  through  the  liver.  The  organ  is  not  only 

*  Alcohol  and  Digestion. — "The  effects  of  alcohol  upon  digestion  vary 
greatly  according  to  the  quantity  imbibed  ;  it  may  act  as  a  temporary  check, 
or  in  large  doses  it  may  completely  arrest  the  digestive  act :  vomiting  is  fre- 
quently induced — the  stomach  thus  freeing  itself  from  the  hurtful  intruder. 
The  habitual  use  of  spirits  often  gives  rise  to  a  most  distressing  form  of  dys- 
pepsia. " 

11.  Effect  upon  the  Appetite. — "At  a  Peace  Congress  held  at  Frankfort, 
Germany,  the  inn-keepers  found  it  necessary  to  increase  the  price  of  board  of 
the  strangers  attending  the  congress,  the  majority  of  whom  were  teetotalers, 
for  the  reason  that  their  appetites  required  an  amount  of  solid  food  in  excess 
of  that  usually  consumed  by  their  own  nationality,  who  are  habitual  drinkers 
of  beer  containing  appreciable  amounts  of  alcohol. 

"  By  direct  contact,  alcohol  acts  upon  the  stomach  and  leads  to  a  destruc- 
tion of  its  secreting  tubules.  Nothing  with  such  certainty  impairs  the  appe- 
tite and  the  digestive  power  as  the  continued  use  of  strong  alcoholic  liquids. 
From  the  stomach  it  is  absorbed,  and  with  its  distribution  through  the  system 
it  interferes  with  nutrition  and  leads  to  a  diseased  state  of  the  liver,  kidneys, 
and  other  organs." — Pavy. 

48.  What  effect  produced  on  the  liver  by  alcohol'/ 


DIGESTION.  127 

diminished  in  size,  but  it  becomes  hardened  and  roughened — an 
appearance  which  has  given  it  the  name  of  hob-nailed  liver  or  drunk- 
ard's liver.  This  condition  not  only  interferes  with  the  proper 
formation  of  bile,  but  it  obstructs  the  return  of  blood  from  the 
organs  in  the  abdomen,  and  we  have  dropsy  as  a  consequence. 

49.  The  Effects  of  Alcohol  on  the  Kidneys.— The  action  of  al- 
cohol on  the  kidneys  is  similar  to  that  which  takes  place  in  the  liver. 
The  first  effect  of  repeated  stimulation  by  alcohol  is  an  increase  of 
the  natural  secretions  of  the  organs,  but  this  continued  over-action,  in 
obedience  to  a  universal  law,  afterward  results  in  a  diminished  secre- 
tion and  in  injury  to  the  substance  of  the  kidney.     "Granular 
degeneration,"  one  of  the  forms  of  Bright's  disease,  takes  place. 
The  kidneys  are  unable  to  perform  efficiently  the  duty  of  removing 
impurities  from  the  blood ;  urea,  and  other  noxious  materials  accu- 
mulate, and  the  whole  system  is  poisoned. 

50.  The  Effect  of  Tobacco  on  Digestion. — Very  few  persons 
are  able  to  take  up  the  habit  of  smoking  without  first  experiencing 
the  sickening  effect  of  tobacco  upon  the  stomach.     The  use  of  to- 
bacco has  a  perverting  influence  over  the  salivary  glands,  causing 
the  secreted  fluid  to  become  so  watery  as  to  deprive  it  of  its  property 
of  converting  starch  into  sugar.     In  the  case  of  some  persons  this 
amounts  to  a  serious  impairment  of  digestion,  and  can  Jbe  relieved 
only  by  the  abandonment  of  the  offending  substance. 

The  habitual  use  of  tobacco  has  a  tendency  to  leave  the  mouth 
and  threat  in  a  condition  of  unnatural  dryness,  and  this  has  the 
effect  of  an  artificially  produced  thirst  which  has,  in  many  instances, 
led  to  the  habit  of  taking  alcoholic  liquors.  These  two  habits  do 
not  always  co-exist  in  the  same  persons,  but  the  danger  that  the  one 
will  lead  up  to  the  other  is  so  great  that  they  are  frequently  spoken 
of  as  the  "  twin  vices." 

The  young  should  appreciate  this  danger,  and  should  also  remem- 
ber that  the  habit  of  using  tobacco  is  most  commonly  established 
early  in  life,  if  at  all ;  very  few  persons,  comparatively,  who  have 
passed  twenty  jears  of  age  without  forming  the  habit,  adopt  it  in 
their  later  years. 

49.  How  are  the  kidneys  affected  by  alcohol  ? 

50.  What  effect  of  tobacco  on  digestion?    Upon  the  mouth?    What  are  the  "twin 
vices"? 


DIGESTION. 


QUESTIONS    FOR    TOPICAL    REVIEW. 

PAGB 

1.  What  do  you  understand  by  nutrition? 104 

2.  How  is  the  process  of  nutrition  carried  on  ? 104 

3.  What  further  can  you  state  on  the  subject? 104 

4.  Desaribe  the  general  plan  of  digestion 105 

5.  How  is  the  process  of  mastication  carried  on  ? 103 

6.  State  what  you  can  in  relation  to  the  formation  of  the  teeth 106,  107 

7.  What,  in  relation  to  their  arrangement  ? 106,  107 

a  What,  in  relation  to  the  process  of  "shedding?"' 106 

9.  In  relation  to  the  different  forms  of  teeth  in  different  animals  ? 103 

10.  What  causes  operate  to  injure  or  destroy  the  teeth  ? 109 

11.  What  suggestions  and  directions  are  given  for  the  preservation  of  the  teeth?. ...  109,  110 

12.  What  do  you  understand  by  insalivation  ? 110 

13.  How  is  the  process  of  insalivation  carried  on? 110,  111 

14.  Of  what  importance  is  the  saliva  to  the  process? Ill 

15.  Of  what  importance  are  mastication  and  insalivation  ? 112 

16.  Describe  the  consequences  of  rapid  eating 113 

17.  What  becomes  of  the  food  directly  after  it  has  undergone  mastication  and  insali- 

vation?   113 

18.  Describe  the  location  and  formation  of  the  stomach 113,  114 

19.  Describe  the  process  by  which  the  gastric  juice  is  formed 114,  115 

20.  What  are  the  properties  and  uses  of  the  gastric  juice  ?^<. 115 

21.  What  are  the  movements  of  the  stomach,  and  what  {heir  uses  ? 115,  116 

22.  What  further  can  you  state  on  the  subject  ? .. 116 

23.  What  portions  of  the  food  are  digested  in  the  stomach  ? 116, 117 

24.  What  are  the  first  changes  of  digestion? 117 

25.  What  further  can  you  state  in  relation  to  the  stomach  ? 117 

26.  Describe  the  intestines 118 

27.  Describe  the  process  of  intestinal  digestion... 118,119 

28.  What  do  you  understand  by  absorption? 119,120 

'29.  How  is  the  process  of  absorption  effected  ? 120 

30.  What  are  the  lacteals,  and  of  what  use  are  they? 121 

31.  What  length  of  time  is  required  for  the  digestion  of  food  ? 121, 122 

32.  What  circumstances,  of  food,  affect  digestion  ? 122 

33.  What  circumstances,  of  emotion,  affect  digestion? 123 

34.  What  suggestions  and  directions  are  given  upon  the  subject  of  eating  and  drinking?.  123 

35.  Describe  the  kidneys  and  their  office 124,125 

36.  What  happens  when  their  action  ceases  ? 125 

37.  Give  the  location  of  the  spleen.     Has  itaduct? 125 

S3.  How  does  alcohol  affect  digestion  ? 125 

39.  Give  the  experiment  on  St.  Martin 126 

40.  State  the  effects  of  alcohol  upon  the  liver 126 

41.  State  the  effects  upon  the  kidneys 127 


» 


/I 


. 


Yt* 


7^  Blood—  Its  Plasma  and  Corpusdea—  Coagulation  of  (h?  Blood  —  The  Uses  of 
the  two/the  Circulation 

if  thf  Heart 
—  The  fre- 

<ph  — 
<  iLe  of  the  (.  Assimilation  —  • 

.  Tfa  Biood.—  Every  M*$  orgeuiiar,  *t  tie  Higher  sell, 

isftf!  or  \^  ^ce  of  life 

•  iistributed 

In  plaii  it  is  a 

rless  blood  ;  in  reptiles  and  fish-  *  cold 

blood;  while  in  the  no,  ds  and  man,  it  is  red  and  warm 

blood. 

2.  TL-'  blocd  is  the  most  impor  it  is  the  most  abundant, 

:  n  definite 

•   '  vory 

as  ejs  '  -J  the 

narration  athe 

voice  of  his  li^^l  orie;  uosaic  law, 

proclaimed  over  thirty  <  >,  the  1                were  forbidden 

to  eat  food  that  eontainc  :  ;hat  "  the  life  of  the 

flesh  is  in  the  blood."  -n  of  a  few  tissues,  such 

as  the  hair,  the  naii  i  the  eye,  blood  everywhere 

pervades  the  body,  a  by  puncturing  any  part  with 


1.  What  is  required  bye  ™--  :5  vine  orowisni?    In  plants!    I;.  >H*?    Man? 

2.  Iiiiiwrtance  an  ;  ienceoflife?    Abei  ?    Mosaic  law?    In 
'•hat  part  of  the  body  i»  bkod  not  fouad ';    Qua&tity  of  blood  IB  tea  body  V 


/ 


"VTI. 

THE  CIRCULATION. 

The  Blood — Its  Plasma  and  Corpuscles — Coagulation  of  the  Blood — The  Uses  of 
the  Blood — Transfusion — Change  of  Color — The  Organs  of  the  Circulation 
— The  Heart,  Arteries,  and  Veins — The  Cavities  and  Valves  of  the  Heart 
—  Its  Vital  Energy — Passage  of  the  Blood  through  the  Heart — The  fre- 
quency and  Activity  of  its  Movements — The  Pulse — The  Spygmograph — 
The  Capillary  Blood-vessels — The  Hate  of  the  Circulation — Assimilation — 
Injuries  to  the  Blood-vessels — Effects  of  Alcohol  on  Heart. 

1.  The    Blood. — Every   living   organism   of   the   higher   sort, 
whether  animal  or  vegetable,  requires  for  the  maintenance  of  life 
and  activity,  a  circulatory  fluid,  hy  which  nutriment  is  distributed 
to  all  its  parts.     In  plants,  this  fluid  is  the  sap ;  in  'insects,  it  is  a 
watery  and  colorless  blood ;  in  reptiles  and  fishes,  it  is  red  but  cold 
blood ;  while  in  the  nobler  animals  and  man,  it  is  red  and  warm 
blood. 

2.  The  blood  is  the  most  important,  as  it  is  the  most  abundant, 
fluid  of  the  body ;  and  upon  its  presence,   under  certain  definite 
conditions,  life  depends.    On  this  account  it  is  frequently,  and  very 
properly,  termed  "  the  vital  fluid."     The  importance  of  the  blood, 
as  essential  to  life,  was  recognized  in  the  earliest  writings.     In  the 
narration  of  the  death  of  the  murdered  Abel,  it  is  written,  "  the 
voice  of  his  blood  crieth  from  the  ground."     In  the  Mosaic  law, 
proclaimed  over  thirty  centuries  ago,  the  Israelites  were  forbidden 
to  eat  food  that  contained  blood,  for  the  reason  that  "  the  life  of  the 
flesh  is  in  the  blood."     With  the  exception  of  a  few  tissues,  such 
as  the  hair,  the  nails,  and  the  cornea  of  the  eye,  blood  everywhere 
pervades  the  body,  as  may  be  proved  by  puncturing  any  part  with 

1.  What  is  required  by  every  living  organism  ?    In  plants?    Insects?    Reptiles?    Man? 

2.  Importance  and  abundance  of  blood  ?    Dependence  of  life  ?    Abel?    Mosaic  law?    In 
what  part  of  the  body  is  blood  uot  found  ?    Quantity  of  blood  in  the  body? 


130 


THE   CIRCULATION. 


a  needle.     The  total  quantity  of  blood  in  the  body  is  estimated  at 
about  one-eighth  of  its  weight,  or  eighteen  pounds. 

3.  The  color  of  the  blood,  in  man  and  the  higher  animals,  as  is 
well  known,  is  red ;  but  it  varies  from  a  bright  scarlet  to  a  dark 
purple,  according  to  the  part  whence  it  is  taken.    "  Blood  is  thicker 
than  water,"  as  the  adage  truly  states,  and  has  a  glutinous  quality. 
It  has  a  faint  odor,  resembling  that  peculiar  to  the  animal  from 
which  it  is  taken. 

4.  When  examined  under  the  microscope,  the  blood  no  longer 
appears  a  simple  fluid,  and  its  color  is  no  longer  red.     It  is  then 
seen  to  be  made  up  of  two  distinct  parts :  first,  a  clear,  colorless 
fluid,  called  the  plasma  ;  and,  secondly,  of  a  multitude  of  minute 
eolid  bodies,  or  corpuscles,  that  float  in  the  watery  plasma.     The 
plasma,  or  nutritive  liquid,  is  composed  of  water  richly  charged  with 
materials  derived   from  the  food,  viz.,  albumen,  which  gives   it 
smoothness  and  swift  motion;  fibrin;  certain  fats;  traces  of  sugar; 
and  various  salts. 

5.  The  Blood  Corpuscles. — In  man,  these  remarkable  "little 
bodies,"  as  the  meaning  of  the  word  corpuscles  signifies,  are  of  a 

yellow  color,  but  by  their  vast  num- 
bers impart  a  red  hue  to  the  blood. 
They  are  very  small,  having  a  diametei 
of  about  -g^-fr  of  an  inch,  and  being 
one-fourth  of  that  fraction  in  thick- 
ness ;  so  that  if  3,500  of  them  were 
placed  in  line,  side  by  side,  they 
would  only  extend  one  inch;  or,  if 
piled  one  above  another,  it  would 
take  at  least  14,000  of  them  to  stand 
an  inch  high.  Although  so  small  in 
size  they  are  very  regular  in  form.  As  seen  under  the  microscope, 
they  are  not  globular  or  spherical,  but  flat,  circular,  and  disc-like, 
with  central  depressions  on  each  side,  somewhat  like  a  pearl  button 
that  has  not  been  perforated.  In  freshly-drawn  blood  they  show  a 
disposition  to  arrange  themselves  in  little  rolls  like  coins  (Fig.  30). 

3.  Color  of  blood?    Its  consistence  ?    Odor? 

4.  What  is  stated  of  the  blaod  as  viewed  under  the  microscope? 

5.  State  what  you  can  of  the  little  bodies  called  corpuscles. 


Fio.  30.— THE  BLOOD  CORPUSCLES, 

HIGHLY  MAGNIFIED. 


THE    CIRCULATION. 


131 


6.  The  size  and  shape  of  blood  corpuscles  vary  in  different  ani- 
mals.    In  man  they  are  circular  and  flat,  with  a  central  depression  on 
both  sides,  also  in  all  warm-blooded  quadrupeds,  except  the  camel  and 
lama,  where  they  are  oval.     In  birds,  reptiles 

§-^«=»               and  fish,  they  are  oval,  but  with  raised  centre  or 
^                 nucleus.     This  variation  is  often  of  vital  im- 
&                  f          portance  in  murder  trials,  where  blood-stained 
weapons  or  clothing  are  used  as  evidence.     A 
microscopical  examination  shows  us  the  cor- 
puscles, and  we  determine  from  their  shape, 
whether  it  was  caused  by  blood  from  a  warm- 
blooded quadruped,  from  a  camel,  or  from  a 
fowl  or  fish.     But  we  cannot  affirm  that  the 
stain  was  made  by  human  blood,  and  not  by 
that  of  the  dog,  ox  or  sheep,  because  in  all 
of  these  the  corpuscles  are  shaped  alike,  and 
ww4es-kttHittte; 


Fir,.  81. 

a,  Oval  Corpuscles  of  a 
fowl,  b,  Corpuscles  of 
a  frog,  c,  Those  of  a 
shark. 

The  five  small  ones  at 
the  upper  part  of  the 
figure,  represent  the  hu- 
man corpuscles  magnified 
four  hundred  times. 


7.  The  character  of  the  blood  of  dead,  ex- 
tinct, and  even  fossil  animal's,  such  as  the 
mastodon,  has  been  ascertained  by  obtaining 
and  examining  traces  of  it  which  had  been  shut 
up,  perhaps  for  ages,  in  the  circulatory  canals 
of  hone.  A  means  of  detecting  blood  in  minute  quantities  is  found 
in  the  spectroscope,  the  same  instrument  by  which  the  constitution 
of  the  heavenly  bodies  has  been  studied.  If  a  solution  containing 
not  more  than  one  one-thousandth  part  of  a  grain  of  the  coloring 
matter  of  the  corpuscle  be  examined,  this  instrument  will  detect  it. 
8.  The  corpuscles  just  described  are  known  as  the  red-blood 
corpuscles.  Besides  these,  and  floating  along  in  the  same  plasma, 
are  the  white  corpuscles.  These  are  fewer  in  number,  but  larger 
and  globular  in  form.  They  are  colorless,  and  their  motion  is  less 
rapid  than  that  of  the  other  variety.  The  total  number  of  both 
varieties  of  these  little  bodies  in  the  blood  is  enormous.  It  is  cal- 
culated that  in  a  cubic  inch  of  that  fluid  there  are  eighty-three 

6.  The  size  and  shape  of  the  corpuscles?    Why  is  the  fact  important? 

7.  The  character  of  the  blood  of  dead  animals  ?    Means  of  detecting  such  blood  ? 

8.  White  corpuscles  ?    Total  number  of  corpuscles  in  the  body  ? 


132  THB   CIRCULATIOH. 

millions,  and  at  least  five  hundred  times  that  number  in  the  whole 
body.     (Read  Note  I. ) 

9.  Coagulation. — The  blood,  in  its  natural  condition  in  the 
body,  remains  perfectly  fluid ;  but  within  a  few  minutes  after  its 
removal  from  its  proper  vessels,  a  change  takes  place.     It  begins  to 
coagulate,  or  assume  a  semi-solid  consistence.     If  allowed  to  stand, 
after  several  hours  it  separates  into  two  distinct  parts,  one  of  them 
being  a  dark  red  jelly,  called  the  coagulum,  or  clot,  which  is  heavy 
and  sinks;  and  the  other,  a  clear,  straw-colored  liquid,  called  serum, 
which  covers  the  clot.     This  change  is  dependent  upon  the  presence 
in  the  blood  of  fibrin,  which  possesses  the  property  of  solidify- 
ing under  certain  circumstances,  one  of  them  being  the  separation 
of  the  blood  from  living  tissues.     The  color  of  the  clot  is  due  to  the 
entanglement  of  the  corpuscles  with  the  fibrin. 

10.  In  this  law  of  the  coagulation  of  the  blood  is  our  safeguard 
against  death  by  hemorrhage,  or  undue  loss  of  blood.     If  coagulation 
were  impossible,  the  slightest  injury  in  drawing  blood  would  prove 
fatal,     Whereas  now,  in  many  cases,  bleeding  ceases  spontaneously, 
because  the  blood,  as  it  coagulates,  stops  the  mouths  of  the  injured 
blood-vessels.     In  another  class  of  cases,  where  larger  vessels  are 
cut  or  torn,  it  is  ordinarily  sufficient  to  close  them  by  a  temporary 

1.  The  Blood—"  You  feel  quite  sure  that  blood  is  red,  do  you  not  ?  Well, 
it  is  no  more  red  than  the  water  of  a  stream  would  be  if  you  were  to  fill  it  with 
little  red  fishes.  Suppose  the  fishes  to  be  very,  very  small — as  small  as  a  grain 
of  sand — and  closely  crowded  together  through  the  whole  depth  of  the  stream, 
the  water  would  look  red,  would  it  not  ?  And  this  is  the  way  iii  which  the 
blood  looks  red :  only  observe  one  thing — a  grain  of  sand  is  a  mountain  in 
comparison  with  the  little  red  bodies  that  float  in  the  blood,  which  we  have 
likened  to  little  fishes.  If  I  were  to  tell  you  they  measured  about  the  3200th 
part  of  an  inch  in  diameter,  you  would  not  be  much  the  wiser ;  but  if  I  tell 
you  that  in  a  single  drop  of  blood,  such  as  might  hang  on  the  point  of  a 
needle,  there  are  a  million  of  these  bodies,  you  will  perceive  that  they  are  both 
very  minute  and  very  numerous.  Not  that  any  one  has  ever  counted  them, 
as  you  may  suppose,  but  this  is  as  close  an  estimate  as  can  be  made  in  view  of 
what  is  known  of  their  minute  size." — Mace's  History  of  a  Mouthful  of  Bread 


9.  The  blood  in  its  natural  condition  in  the  body?    Describe  the  process  by  which  the 
coagulation  of  blood  takes  place? 
10.  If  coagulation  were  impossible?    How  is  it  in  fact? 


THE   CIRCULATION.  133 

pressure  ;  for  in  a  few  minutes  the  clot  will  form  and  seal  them  up. 
In  still  more  serious  cases,  where  the  blood-vessel  is  of  large  size, 
the  surgeon  is  obliged  to  tie  a  ligature  about  it,  thus  preventing  the 
force  of  the  blood-current  from  washing  away  the  clots,  whicht 
forming  within  and  around  the  vessel,  close  it  effectually. 

II.  It  is  worthy  of  remark  that  this  peculiarity  is  early  implanted 
in  the  blood,  even  before  birth,  and  in  advance  of  any  existing 
necessity  for  it — thus  anticipating  and  guarding  against  danger.  But 
this  is  not  alL  Of  most  of  the  inferior  animals,  which,  as  compared 
with  man,  are  quite  helpless,  the  blood  coagulates  more  rapidly, 
and  in  the  case  of  the  birds,  almost  instantly.  The  relative  com- 
position of  fluid  and  coagulated  blood  may  be  thus  represented : 

Fluid  Blood.  Coagulated  Blood. 

-Serum 


Corpuscles Corpuscl 

(See  Appendix,  page  306.) 

12.  The  Uses  of  the  Blood. — The  blood  is  the  great  provider 
and  purifier  of  the  body.  It  both  carries  new  materials  to  all  the 
tissues,  and  removes  the  worn-out  particles  of  matter.  This  is 
effected  by  the  plasma.  It  both  conveys  oxygen  and  removes  car- 
bonic acid.  This  is  done  through  the  corpuscles.  Some  singular 
experiments  have  been  tried  to  illustrate  the  life-giving  power  of 
the  blood.  An  animal  that  has  bled  so  freely  as  to  be  at  the  point 
of  death,  is  promptly  brought  back  to  life  by  an  operation  called 
transfusion,  by  which  fresh  blood  from  a  living  animal  is  injected 
into  the  blood-vessels  of  his  body.  (Read  Note  2.) 

2.  The  Work  of  the  Blood.—"  The  blood,  which  is  our  life,  is  a  complex 
fluid.  It  contains  the  materials  out  of  which  the  tissues  are  made,  and  also 
the  debris  which  results  from  the  destruction  of  the  same  tissues, — the  worn- 
out  cells  of  brain  and  muscle,— the  cast-off  clothes  of  emotion,  thought,  and 
power.  It  is  the  common  carrier,  conveying  unceasingly  to  every  gland  and 

11.  What  is  worthy  of  remark?    Coagulation  of  the  blood  of  inferior  animals?    Of  the 
blood  of  birds? 

12.  The  blood,  as  a  provider  and  purifier?    What  uses  does>the  blood  subserve  ?    Expert 
menta  ?    Transfusion  ¥ 


134  THE   CIRCULATION. 

13.  It  is  related  that  a  dog,  deaf  and  feeble  from  age,  had  hearing 
and  activity  restored  to  him  by  the  introduction  into  his  veins  of 
blood  taken  from  a  young  dog ;  and,  that  a  horse,  twenty-six  years 
old,  having  received  the  blood  of  four  lambs,  acquired  new  vigor. 
And  further,  that  a  dog,  just  dead  from  an  acute  disease,  was  so  far 
revived  by  transfusion,  as  to  be  able  to  stand  and  make  a  few 
movements. 

14.  Transfusion  has  been  practiced  upon  man.     At  one  time, 
shortly  after  Harvey's  discovery  of  the   "Circulation  of  the  Blood," 
it  became  quite  a  fashionable  remedy,  it  being  thought  possible  by 
it  to  cure  all  forms  of  disease,  and  even  to  make  the  old  young  again. 
But  these  claims  were  soon  found  to  be  extravagant,  and  many  un- 
happy accidents  occurred  in  its  practice ;  so  that  being  forbidden  by 
government  and  interdicted  by  the  Pope,  it  rapidly  fell  into  disuse. 
At  the  present  time,  however,  it  is  sometimes  resorted  to  in  extreme 
cases,  when  there  has  been  a  great  and  rapid  loss  of  blood  ;  and  there 
are  upon  record   several    instances    where,   other   means  having 
failed,  life  has  been   restored  or  prolonged  by  the  operation  of 
transfusion. 

15.  This  reviving  power  of  the  blood  seems  to  reside  in  the  cor- 
puscles ;  for  transfusion,  when  performed  with  the  serum  alone,  has, 
in  every  case,  proved  fruitless.     Now,  though  so  much  depends 
upon  the  blood  and  its  corpuscles,  it  is  a  mistake  to  suppose  that  in 
them  alone  is  the  seat  of  life,  or  that  they  are,  in  an  exclusive 
manner,    alive.       All    the    organs   and   parts   of   the   body  are 
mutually    dependent    one    upon    the    other,   and    the    complete 
usefulness  of  any  part  results  from  the  harmonious  action  of  the 
whole. 

organ,  the  fibrin  and  albumen  which  repair  their  constant  waste,  thus  supply- 
ing their  daily  bread.  Like  the  water  flowing  through  the  canals  of  Venice, 
that  carries  health  and  wealth  to  the  portals  of  every  house,  and  filth  and 
disease  from  every  doorway,  the  blood  flowing  through  the  canals  of  OUT 
organization  carries  nutriment  to  all  tissues,  and  refuse  from  them." — Clarke' i 
Sex  in  Education. 

13.  The  case  of  the  deaf  and  feeble  dog  ?    Horse?    Dead  dog  T 

14.  Transfusion,  as  a  fashionable  remedy  ?    What  further  of  transfusion? 

15.  The  seat  of  the  reviving  pu war  oi  the  blood  f    What  further  is  related  1 


THE   CIRCULATION.  135 

16.  Change  of  Color. — The  blood  undergoes  a  variety  of  changes 
in  its  journey  through  the  system.  As  it  visits  the  different  organs 
it  both  gives  out  and  takes  up  materials.  In  one  place  it  is 
enriched,  in  another  it  is  impoverished.  By  reason  of  these 
alterations  in  its  composition,  the  blood  also  changes  its  color.  In 
one  part  of  the  body  it  is  bright  red,  or  arterial ;  in  another  it  is 
dark  blue,  or  venous.  In  the  former  case  it  is  pure,  and  fit  for  the 
support  of  the  tissues ;  in  the  latter,  it  is  impure  and  charged  with 
effete  materials.  (The  details  of  the  change  from  dark  to  bright 
will  be  given  in  the  chapter  on  Respiration.)  (Read  Notes  3 
and  4. )  (See  Appendix,  page  306.) 

3.  On  Purifying  the  Blood.—"  By  some  the  blood  is  regarded  as  the 
source  of  all  diseases,  and  to  '  purify  the  blood '  is  the  object  of  their  treat- 
ment.    Quacks  seize  on  this  notion,  and  in  sublime  ignorance  of  the  nature  of 
the  blood  they  profess  to  purify,  and  of  the  means  by  which  their  drugs  could 
possibly  purify  it,  make  fortunes  out  of  the  credulity  of  the  public.      I  would 
warn  you  against  this  notion  of  *  purifying '  the  blood.       The  blood  is  not 
like  a  river  into  which  anything  can  be  introduced  from  without.     It  gets  rid 
of,  or  destroys,  all  substances  which  intrude — all  which  do  not  form  part  and 
parcel  of  its  own  structure ;  or,  failing  in  that,  it  ceases  to  act  as  living  blood." 
— George  Henry  Lewes. 

4.  By  Means  of  the  Blood,  Exercise  Benefits  the  Whole  Body. — 
"  The  employment  of  the  muscles  in  exercise  not  only  benefits  their  especial 
structure,  but  it  acts  on  the  whole  system.     When  the  muscles  are  put  in 
action,  the  capillary  blood-vessels  with  which  they  are  supplied  become  more 
rapidly  charged  with  blood,  and  active  changes  take  place,  not  only  in  the 
muscles,  but  in  all  the  surrounding  tissues.    The  heart  is  thus  required  to  supply 
more  blood,  and  accordingly  beats  more  rapidly  in  order  to  supply  the  demand. 
A  large  quantity  of  blood  is  sent  through  the  lungs,  and  larger  supplies  of 
oxygen  are  taken  in  and  carried  to  the  various  tissues  of  the  body. "      The 
oxygen  engenders  a  large  amount  of  heat,  which  produces  an  action  on  the 
skin  whereby  the  increase  of  heat  may  be  got  rid  of.      By  this  means  the  skin 
is  exercised,  the  perspiration  is  poured  forth,  the  surface  is  caused  to  glow  and 
is  kept  in  health.      ' '  Not  only  are  these  organs  benefited  by  the  increased 
circulation  of  the  blood,  produced  by  exercise,  but  wherever  the  blood  is  sent, 
changes  of  a  healthful  character  occur.     The  brain  and  the  rest  of  the  nervous 
system  are  invigorated  ;  the  stomach  has  its  powers  of  digestion  improved  ; 
and  the  liver,  pancreas,  and  other  organs  perform  their  functions  with  more 
vigor." — Lankester's  Manual  of  Health. 


18.  Changed  iu  the  blood  ?     What  further  is  stated  f 


136  THE   CIRCULATION. 

17.  Circulation. — The  blood  is  in  constant  motion  during  life. 
From  the  heart,  as  a  centre,  a  current  is  always  setting  toward  the 
different  organs ;  and  from  these  organs  a  current  is  constantly  re- 
turning to  the  heart.     In  this  way  a  ceaseless  circular  movement  is 
kept  up,  which  is  called  the  Circulation  of  the  Blood.    This  stream 
of  the  vital  fluid  is  confined  to  certain  fixed  channels — the  blood- 
vessels.   Those  branching  from  the  heart  are  the  arteries  ;  those  con- 
verging to  it   are  the  veins.     The  true  course  of  the  blood  was 
unknown  before  the  beginning  of  the  seventeenth  century.    In  1 6 1 9 
it  was  discovered  by  the  illustrious  William  Harvey.     Like  many 
other  great  discoverers,  he  suffered  persecution  and  loss,  but  unlike 
some  of  them,  he  was  so  fortunate  as  to  conquer  and  survive  opposi- 
tion.   He  lived  long  enough  to  see  his  discovery  universally  accepted, 
and  himself  honored  as  a  benefactor  of  mankind. 

18.  The  Heart. — The  heart  is  the  central  engine  of  the  circula- 
tion.    In  this  wonderful  little  organ,  hardly  larger  than  a  man's  fist, 
resides  that  sleepless  force  by  which,  during  the  whole  of  life,  the 
current  of  the  blood  is  kept  in  motion.      It  is  placed  in  the  middle 
and  front  part  of  the  chest,  inclining  to  the  left  side.      The  heart- 
beat may  be  felt  and  heard  between  the  fifth  and  sixth  ribs,  near 
the  breastbone.      The  shape  of  the  heart  is  conical,  with  the  apex 
or  point  downward  and  in  front.      The  base,  which  is  upward,  is 
attached  so  as  to  hold  it  securely  in  its  place,  while  the  apex  is 
freely  movable.      In  order  that  loss  of  power  from  friction  may  be 
obviated,  the  heart  is  enclosed  between  two  layers  of  serous  mem- 
brane, which   forms  a  kind  of   sac.     This   membrane,  called  the 

pericardium,  is  as  smooth  as  satin,  and  itself  secretes  a  fluid  in 
sufficient  quantities  to  keep  it  at  all  times  well  lubricated.  The 
lining  membrane  of  the  heart,  called  the  endocardium,  is  extremely 
delicate  and  smooth.  (Read  Note  5. ) 

5.  A  Poet's  Summary  of  the  Circulation: — 

"  The  smooth,  soft  air  with  pulse-like  waves 
Flows  murmuring  through  its  hidden  caves, 


IT.  Motion  of  the  blood?  What  is  meant  by  the  circulation  of  the  blood  ?  How  confined? 
Discovery  made  by  Harvey  ? 

18.  Office  of  the  heart  ?  Location  of  the  heart  ?  Its  beat  ?  Its  shape  ?  Protection  to  the 
heart  ?  What  else  is  said  in  relation  to  the  heart  ? 


THE   CIRCULATION.  137 

19.  The  Cavities  of  the  Heart. — The  heart  is  hcllow,  and  so 
partitioned  as  to  contain  four  chambers  or  cavities ;  two  at  the  base, 
known  as  the  auricles,  from  a  fancied  resemblance  to  the  ear  of  a 
dog,  and  two  at  the  apex  or  point,  called  ventricles.     An  auricle  and 
a  ventricle  on  the  same  side  communicate  with  each  other,  but  there 
is  no  opening  from  side  to  side.     It  is  customary  to  regard  the 
heart  as  a  double  organ,  and  to  speak  of  its  division  into  the  right 
and  left  heart.     For  while  both  halves  act  together  in  point  of 
time,  each  half  sustains  an  entirely  distinct  portion  of  the  labor  of 
the  circulation.     The  right  side  always  carries  the  dark  or  venous 
blood,  and  the  left  always  circulates  the  bright  or  arterial  blood. 

20.  If  we  examine  the  heart,  we  at  once  notice  that,  though  its 
various  chambers  have  about  the  same  capacity,  the  walls  of  the 
ventricles  are  thicker  and  stronger  than  those  of  the  auricles.     This 
is  a  wise  provision,  for  it  is  by  the  powerful  action  of  the  ventricles 
that  the  blood  is  forced  to  the  most  remote  regions  of  the  body. 
The  auricles,  on  the  contrary,  need  much  less  power,  for  they  sim- 
ply discharge  their  contents  into  the  ventricles  below  them.   '  (Figs. 
32  and  33.)     (See  Appendix,  page  306.) 

21.  Action  of  the  Heart. — The  substance  of  the  heart  is  of  a 
deep  red  color,  and  its  fibres  resemble  those  of  the  voluntary  mus- 

Whose  streams  of  brightening  purple  rush, 
Fired  with  a  new  and  livelier  blush  ; 
While  all  their  burden  of  decay 
The  ebbing  current  steals  away, 
And,  red  with  Nature's  flame,  they  start 
From  the  warm  fountains  of  the  heart. 
"  No  rest  that  throbbing  slave  may  ask, 
Forever  quivering  o'er  his  task, 
While  far  and  wide  a  crimson  jet 
Leaps  forth  to  fill  the  woven  net, 
Which,  in  unnumbered  crossing  tides, 
The  flood  of  burning  life  divides  ; 
Then,  kindling  each  decaying  part. 
Creeps  back  to  find  the  throbbing  heart." 

— Dr.  0.  W.  Holmes. 

19.  Formation  of  the  heart?    Right  and  left  heart  ? 

20.  Capacity  of  the  chambers  of  the  heart?    What  wise  provision  is  mentioned?    The 
auricles? 

21.  Substance  of  the  heart?    Its  fibres?    Its  movements?    The  advantage  of  such  move- 
ments ?    Action  of  the  heart  ?    Its  period  of  repose  ? 


138 


CIRCULATION. 


cles  by  which  we  move  our  limbs.     But  the  heart's  movements  are 
entirely  involuntary.     The  advantage  of  this  is  evident;  for  if  it 

depended  upon  us  to  will 
each  movement,  our  entire 
attention  would  be  thus  en- 
gaged, and  we  would  find  no 
time  for  study,  pleasure,  or 
even  sleep.  The  action  of 
the  heart  consists  in  alter 
nate  contractions  and  expan- 
sions. During  contraction 
the  walls  come  forcibly  to- 
gether, and  thus  drive  out 
the  blood.  They  then  ex- 
pand and  receive  a  renewed 
supply.  These  movements 
are  called  respectively  systole 
and  diastole.  The  latter  may 

PlO.  84.-SECTION  OF  THE  HEART.  ^     ^^    ^Q     ^rfs   period 

A,  Right  Ventricle.       E,  F,  Inlets  to  the  Ventricles,  of   TCDOSe  :    and    although   it 

B,  Left  "  G,  Pulmonary  Artery. 

c,  night  Auricle.        H,  Aorta.  lasts  only  during  two-fifths 

D,  Left  Auricle.  J    . 

of  a  heart-beat,  or  about  a 

third  of  a  second,  yet  during  the  day  it  amounts  to  more  than 
nine  hours  of  total  rest. 

22.  A  remarkable  property  of  the  tissue  of  the  heart  is  its  in- 
tense vitality.  For  while  it  is  more  constantly  active  than  any 
other  organ  of  the  body,  it  is  the  last  to  part  with  its  vital  energy. 
This  is  especially  interesting  in  view  of  the  fact  that  after  life  is 
apparently  extinguished,  as  from  drowning,  or  poisoning  by  chloro- 
form, there  yet  lingers  a  spark  of  vitality  in  the  heart,  which,  by 
continued  effort,  may  be  fanned  into  a  flame  so  as  to  revivify  tho 
whole  body.  In  cold-blooded  animals,  this  irritability  of  the  heart 
is  especially  remarkable.  The  heart  of  a  turtle  will  pulsate,  and 
the  blood  circulate  for  a  week  after  its  head  has  been  cut  off;  and 
its  heart  will  throb  regularly  many  hours  after  being  cut  out.  The 


22.  Remarkable  property  of  the  tissue  of  the  heart?    How  shown?    How  interesting? 
In  cold-blooded  animals?    Heart  of  a  turtle  ?    Of  a  frog?    Alligator? 


THE    CIBCULATION.  139 

heart  of  a  frog  or  serpent,  separated  entirely  from  the  body,  will 
contract  at  the  end  of  ten  or  twelve  hours ;  that  of  an  alligator  has 
been  known  to  beat  twenty-eight  hours  after  the  death  of  the  ani- 
mal 

23.  Passage  of  the  Blood  through  the  Heart. — Let  us  now 
trace  the  course  of  the  blood  through  the  several  cavities  of  the 
heart.     In  the  first  place,  the  venous  blood,  rendered  dark  and  im- 
pure by  contact  with  the  changing  tissues  of  the  body,  returns  to 
the  right  heart  by  the  veins.     It  enters  and  fills  the  right  auricle 
during  its  expansion ;  the  auricle  then  contracts  and  fills  the  right 
ventricle.     Almost  instantly,  the  ventricle  contracts  forcibly  and 
hurries  the  blood  along  the  great  artery  of  the  lungs,  to  be  purified 
in  those  organs.     Secondly,  having  completed  the  circuit  of  the 
lungs,  the  pure  and  bright  arterial  blood  enters  the  left  auricle. 
This  now  contracts  and  fills  the  left  ventricle,  which  cavity,  in  its 
turn,  contracts   and   sends   the   blood  forth  on  its  journey  again 
through  the  system.     This  general  direction  from  right  to  left  is 
the  uniform  and  undeviating  course  of  heart-currents. 

24.  The  mechanism  which  compels  this  regularity  is  as  simple 
as  it  is  beautiful.     Each  ventricle  has  two  openings,  an  inlet  and 
an  outlet,  each  of  which  is  guarded  by  strong  curtains,  or  valves. 
These  valves  open  freely  to  admit  the  blood  entering  from  the  right, 
but  close  inflexibly  against  its  return.     Thus,  when   the   auricle 
contracts,  the  inlet  valve  opens ;  but  as  soon  as  the  ventricle  begins 
to  contract,  it  closes  promptly.     The  contents  are  then,  so  to  speak, 
cornered,  and  have  but  one  avenue  of  escape — that  through  the  out- 
let valve  into  the  arteries  beyond.     As  soon  as  the  ventricle  begins 
to  expand  again,  this  valve  shuts  tightly  and  obstructs  the  passage 
The  closing  of  these  valves  occasions  the  two  heart-sounds,  which 
we  hear  at  the  front  of  the  chest.     (Figs.  35  and  36.) 

25.  Frequency  of  the   Heart's   Action. — The  alternation  of 
contraction  and  expansion  constitutes  the  heart-beats.     These  fol- 
low each  other  not  only  with  great  regularity,  but  with  great  rapid- 
ity.    The  average  number  in  an  adult  man  is  about  seventy-two  in 

23.  Course  of  the  blood  through  the  heart?    Course  of  heart-currents  ? 

24.  Openings  of  the  ventricles  ?    How  guarded  ?    How  do  the  valves  operate  ?    The  con- 
sequence ?    Heart-sounds  ? 

25.  Heart-beats?    The  heart  as  a  susceptible  organ?    Heat,  exercise,  etc.  ? 


140  THE   CIRCULATION. 

a  minute.  But  the  heart  is  a  susceptible  organ,  and  many  circum* 
stances  affect  its  rate  of  action.  Heat,  exercise,  and  food  increase 
its  action ;  cold,  fasting,  and  sleep  diminish  it.  Posture,  too,  has  a 
curious  influence ;  for  if  while  sitting  the  beats  of  the  heart  number 
seventy-one,  standing  erect  will  increase  them  to  eighty-one,  and 
lying  down  will  lower  them  to  sixty-six.  (Read  Note  6. ) 

26.  The  modifying  influence  of  mental  emotions  is  very  power- 
ful Sudden  excitement  of  feeling  will  cause  the  heart  to  palpitate, 
or  throb  violently.  Depressing  emotions  sometimes  temporarily 
interrupt  its  movements,  and  the  person  faints  in  consequence. 
Extremes  of  joy,  grief,  or  fear  have  occasionally  suspended  the 
heart's  action  entirely,  and  thus  caused  death.  The  rate  of  the 
heart-beat  may  be  naturally  above  or  below  seventy-two.  Thus  ii 
is  stated  that  the  pulse  of  the  savage  is  always  slower  than  that  of 
the  civilized  man.  Bonaparte  and  Wellington  were  very  much 
alike  in  their  heart  pulsations,  which  were  less  than  fifty  in  the 
case  of  each.  (Read  Note  7. ) 

6.  The  Heart  is  Injured  by  Over-exertion. — "During  exertion,  if 
the  heart  is  not  oppressed,  its  movements,  though  rapid  and  forcible,  are  regu- 
lar and  equal.     But  when  it  becomes  embarrassed,  the  pulse-beats  are  quick, 
unequal,  and  at  last  become  irregular,  indicating  injury  to  the  organ.     All 
great  and  sudden  efforts  are  to  be  carefully  avoided;  excessive  exercise  often 
produces  palpitation,  and  sometimes  enlargement  and  valvular  disease  of  the 
heart." — Huxley. 

"No  great  intellectual  thing  was  ever  done  by  great  effort;  a  great  thing 
can  only  be  done  by  a  great  man,  and  he  does  it  without  effort.  The  body's 
work  and  the  head's  work  are  to  be  done  quietly,  and  comparatively  without 
effort.  Neither  limbs  or  brain  are  ever  to  be  strained  to  their  utmost ;  that  is 
not  the  way  in  which  the  greatest  quantity  of  work  is  to  be  got  out  of  them; 
they  are  never  to  be  worked  furiously,  but  with  tranquillity  and  constancy. 
We  are  to  follow  the  plow  from  sunrise  to  sunset,  but  not  to  pull  in  race- 
boats  at  the  twilight ;  we  shall  get  no  fruit  of  that  kind  of  work— only  disease 
of  the  heart. " — RusTcin. 

7.  Fainting. — "When  the  heart  suddenly  ceases  to  act,  fainting  or  swoon- 
ing is  very  apt  to  take  place.     This  takes  place  for  the  reason  that  the  brain 
feels  most  speedily  the  lack  of  its  supply  of  blood.     Many  circumstances  may 
cause  a  faint — such  as  a  fright,  joy,  excitement,  the  sight  of  blood,  or  the 
breathing  of  foul  air;  or  it  may  be  due  to  disease  of  the  heart     In  some  per- 

26.  Mental  emotions?  Sudden  excitement?  Excessive  joy?  The  heart-beat  rat*?  Bo- 
uaparte  and  Wellington? 


"-- -T 

SUPERIOR  || 
VENACAVA  if 


THE    CIRCULATION.  141 

27.  Activity  of  the  Heart.  —The  average  number  of  heart-beats 
during  a  lifetime  may  be  considered  as  at  the  rate  of  seventy-two 
per  minute,  although  this  estimate  is  somewhat  low,  for  during  sev- 
eral years  of  early  life  the  rate  is  above  one  hundred  a  minute. 
In  one  hour,  then,  the  heart  pulsates  four  thousand  times ;  in  a 
day,  one  hundred  thousand  times ;  and  in  a  year,  nearly  thirty-eight 
million  times.  If  we  compute  the  number  during  a  lifetime — forty 
years  being  the  present  average  longevity  of  civilized  mankind — we 
obtain  as  the  vast  aggregate,  fifteen  hundred  millions  of  pulsations. 
(Read Note  %.} 

sons,  fainting  becomes  a  kind  of  habit;  they  fall  into  a  fainting  fit  on  very 
slight  agitation.  In  them  the  appearances  are  much  worse  than  the  reality, 
especially  to  those  who  are  not  familiar  with  the  ailment.  But  persons  who 
faint  after  exhaustion,  fatigue,  fasting,  or  anguish,  require  prompt  attention. 
The  ordinary  signs  are  great  pallor,  loss  of  sensation,  and  trembling  of  the 
limbs  and  loss  of  power  over  the  muscles  ;  the  breathing  and  pulse  go  on  im- 
perfectly or  stop.  The  first  thing  to  do  is  to  place  the  head  low,  thus  favoring 
the  supply  of  blood  to  the  brain;  the  very  act  of  falling  is  often  sufficient  to 
restore  consciousness.  Water  may  be  sprinkled  on  the  face,  hartshorn  held  to 
the  nose,  or  mustard  over  the  heart.  Pure  air  is  a  great  restorative  ;  allow  a 
current  of  fresh  air  to  flow  over  the  face,  and  loosen  any  tight  bands  that  may 
confine  the  chest." — Dr.  J.  Knight  (in part). 

8.  The  Heart  a  Vital  Machine. — "The  heart  is  a  machine.  It  is  an 
organ  constructed  of  muscular  chambers  and  communicating  passages,  and 
supplied  with  mechanical  contrivances,  adapted  to  guide  the  stream  of  blood 
passing  through  it,  and  to  prevent  a  reflux  in  the  backward  direction.  Does 
not  this  take  away  wonderfully  from  the  character  of  fanciful  mystery  with 
which  poets  and  sentimentalists  have  invested  it  ?  The  heart  that  we  have 
always  heard  of  as  the  centre  of  the  affections,  the  home  of  sensibility,  the 
dwelling-place  of  courage,  of  faith,  of  hope,  and  all  the  rest  of  the  virtues,  is 
after  all,  nothing  but  an  organ  to  serve  for  the  impulsion  of  the  blood — a  mere 
force-pump,  a  machine.  Does  not  this  bring  down  our  ideas,  and  show  that 
no  poetical  mystery  can  escape  the  searching  investigation  of  the  anatomist  1 
Not  at  all. 

"For  this  machine  that  we  carry  about  with  us  in  our  breasts  is  alive. 
There,  at  its  post,  at  the  central  point  of  the  circulation,  with  the  soft  lobes  of 
the  lungs  folded  round  it  like  a  curtain,  it  contracts  and  relaxes,  and  relaxes 
and  contracts,  with  a  steady  and  unremitting  industry  that  by  itself  is  some- 
thing worthy  of  our  admiration.  No  other  muscle  in  the  body  can  do  this. 
By  some  incomprehensible  vitality  of  its  own,  it  keeps  up  its  rhythmical  con« 

tf.  Average  number  of  heart-be^?    Inonelwuj:?    Year?    Lifetime  J 


142  THE   CIRCULATION. 

28.  Again,  if  we  estimate  the  amount  of  blood  expelled  by  each 
contraction  of  the  ventricles  at  four  ounces,  then  the  weight  of  the 
blood  moved  during  one  minute  will  amount  to  eighteen  pounds. 
In  a  day  it  will  be  about  twelve  tons ;  in  a  year,  four  thousand 
tons ;  and  in  the  course  of  a  lifetime  over  one  hundred  and  fifty 
thousand  tons.     These  large  figures  indicate,  in  some  measure,  the 
immense  labor  necessary  to  carry  on  the  interior  and  vital  operations 
of  our  bodies.     In  this  connection,  we  call  to  mind  the  fanciful 
theories  of  the  ancients  in  reference  to  the  uses  of  the  heart.     They 
regarded  it  as  the  abode  of  the  soul  and  the  source  of  the  nobler 
emotions — bravery,  generosity,  mercy,  and  love.     The  words  cour- 
age and  cordiality  are  derived  from  a  Latin  word  signifying  heart. 
Many  other  words  and  phrases,  as  hearty,  heart-felt,  to  learn  by 
heart,  and  large-hearted,  show  how  tenaciously  these  exploded  opin- 
ions have  fastened  themselves  upon  our  language. 

29.  At  the  present  time,  the  tendency  is  to  ascribe  purely  me- 
chanical functions  to  the  heart.     This  view,  like  the  older  one,  is 
inadequate ;  for  it  expresses  only  a  small  part  of  our  knowledge  of 
this  organ.     The  heart  is  unlike  a  simple  machine,  because  its  mo- 
tive power  is  not  applied  from  without,  but  resides  in  its  own  sub- 
stance.    Moreover,  it  repairs  its  own  waste,  it  lubricates  its  own 
action,  and  it  modifies  its  movements  according  to  the  varying  needs 
of  the  system.     It  is  more  than  a  mere  force-pump,  just  as  the 
stomach  is  something  more  than  a  crucible,  and  the  eye  something 
more  than  an  optical  instrument.     (Read  Note  9.) 

tractions  without  the  aid  of  our  will  and  even  without  our  knowledge.  While 
you  are  asleep  and  while  you  are  awake,  from  the  first  moment  of  your  birth, 
even  from  before  your  birth,  up  to  the  present  time,  it  has  never  for  one  mo- 
ment stopped  or  nagged  in  its  movements,  for  if  it  were  to  do  so  death  would 
be  the  result.  "—Dr.  J.  C.  Dalton. 

9.  The  Heart. — "You  all  know  where  it  is.  It  is  the  most  wonderful 
little  pump  in  the  world.  There  is  no  steam-engine  half  so  clever  at  its  work, 
or  so  strong.  There  it  is,  in  every  one  of  us,  beat,  beating — all  day  and  all 
night,  year  after  year,  never  stopping,  like  a  watch  ticking ;  only  it  never 
needs  to  be  wound  up, — God  winds  it  up  once  for  all." — Author  of  "Rob  and 
His  Friends."  

28.  Amount  of  blood  expelled  ?    Theories  of  the  ancients  ? 

39.  The  tendency  at  the  present  tiine  ?    Why  is  this  view  inadequate  ? 


THE   CIRCULATION.  143 

30.  The  Arteries. — The  tube-like  canals  which  carry  the  blood 
away   from  the  heart  are  the  arteries.     Their  walls  are  made  of 
tough,  fibrous  materials,  so  that  they  sustain  the  mighty  impulse  of 
the  heart,  and  are  not  ruptured.     In  common  with  the  heart,  the 
arteries  have  a  delicately  smooth  lining  membrane.     They  are  also 
elastic,  and  thus  re-enforce  the  action  of  the  heart ;  they  always 
remain  open  when  cut  across,  and  after  death  are  usually  found 
empty. 

31.  The  early  anatomists  observed  this  condition,  and  supposing 
that  it  existed  during  life,  came  to  the  conclusion  that  these  tubes 
were  designed  to  act  as  air-vessels — hence  the  name  artery,  from 
Greek  words  which  signify  "  containing  air."     This  circumstance 
affords  us  an  illustration  of  the  mistaken  notions  of  the  ancients  in 
reference  to  the  internal  operations  of  the  body.     Cicero  speaks  of 
the  arteries  as  "  conveying  the  breath  to  all  parts  of  the  body." 

32.  The  arterial  system  springs  from  the  heart  by  a  single  trunk, 
like  a  minute  and  hollow  tree,  with   numberless   branches.     As 
these  branches  leave  the  heart,  they  divide  and  subdivide,  continu- 
ally growing  smaller  and  smaller,  until  they  can  no  longer  be  traced 
by  the  naked  eye.     If,  then,  we  continue  the  examination  by  the 
aid  of  a  microscope,  we  see  these  small  branches  sending  off  still 
smaller  ones,  until  all  the  organs  of  the  body  are  penetrated  by 
arteries. 

33.  The  Pulse. — With  each  contraction  of  the  left  side  of  the 
heart,  the  impulse  causes  a  wave-like  motion  to  traverse  the  entire 
arterial  system.     If  the  arteries  were  exposed  to  view,  we  might  see 
successive  waves  speeding  from  the  heart  to  the  smallest  of  the 
branches,  in  about  one-sixth  part  of  a  second.     The  general  course 
of  the  arteries  is  as  far  as  possible  from  the  surface.     This  arrange- 
ment is  certainly  wise,  as  it  renders  them  less  liable  to  injury — the 
wounding  of  an  artery  being  especially  dangerous.     It  also  protects 
the  arteries  from  external  and  unequal  pressure,  by  which  the  force 
of  the  heart  would  be  counteracted  and  wasted.     Accordingly,  we 


30.  What  are  the  arteries?    Their  walls?    Their  membrane? 

31.  Early  anatomists  ?    The  service  of  the  illustration? 

32.  The  arterial  system?    The  branches  and  sub-branches  of  the  arteries? 

33.  Successive  undulations  from  the  heart?    Course  of  the  arteries ?    Protection  of  th« 
arteries  ?    General  location  of  the  arteries  ? 


144  THE  CIRCULATION 

generally  find  these  vessels  close  to  the  bones,  or  niding  behind  the 
muscles  and  within  the  cavities  of  the  body. 

34.  In  a  few  situations,  however,  the  arteries  lie  near  the  sur- 
face ;  and  if  we  apply  the  finger  to  any  of  these  parts,  we  shall  dis- 
tinctly feel  a  throbbing  motion  taking  place  in  harmony  with  the 
heart-beat.     This  is  part  of  the  wave-motion  just  mentioned,  and  is 
known  as  the  pulse.     All  are  familiar  with  the  pulse  at  the  wrist, 
in  the  radial  artery ;  but  it  is  not  peculiar  to  that  position,  for  it 
may  be  felt  in  the  carotid  of  the  neck,  in  the  temporal  at  the  tem- 
ple, and  elsewhere,  especially  near  the  joints.. 

35.  Since  the  heart-beat  makes  the  pulse,  whatever  affects  the 
former  affects  the  latter  also.     Accordingly,  the  pulse  is  a  good  index 
of  the  state  of  the  health,  so  far  as  the  health  depends  upon  the 
action  of  the  heart.     It  informs  the  physician  of  the  condition  of 
the  circulation  in  four  particulars — its  rate,  regularity,  force,  and 
fullness  i  and  nearly  every  disease  modifies  in  some  respect  the  con- 
dition of  the  pulse.     A  very  ingenious  instrument,  known  as  the 
sphygmograph,  or  pulse-writer,  has  recently  been  invented,  by  the 
aid  of  which  the  pulse  is  made  to  write  upon  paper  its  own  signa- 
ture, or  rather  to  sketch  its  own  profile.     This  instrument  shows 


FIG.  37.— THE  FORM  OF  THE  PUME. 

with  great  accuracy  the  difference  between  the  pulses  of  health  and 
those  of  disease.  In  Fig.  37  is  traced  the  form  of  the  pulse  in 
health,  which  should  be  read  from  left  to  right.  That  part  of  the 
trace  which  is  nearly  perpendicular  coincides  with  the  contraction 
of  the  ventricles,  while  the  wavy  portion  marks  their  dilatation. 
(Read  Note  10.) 

10.  The  Beating  of  the  Pulse. — "According  to  experiments  made  in 
Paris,  the  pulse  of  a  lion  beats  forty  times  a  minute  ;  that  of  a  tiger,  ninety- 

84.  Where  do  the  arteries  lie  ?    If  we  apply  the  finger  ?    Pulse  ?    Where  felt  ? 
35.  The  pulse  as  an  index?    Of  what  does  it  inform  the  physician?    Instrument  for  r» 
cording  pulsation  f 


THE   CIRCULATION.  145 

36.  The  Veins. — The  vessels  by  which  the  blood  returns  to  the 
heart  are  the  veins.     At  first  they  are  extremely  small ;  but  uniting 
together  as  they  advance,  they  constantly  increase  in  size,  remind- 
ing us  of  the  way  in  which  the  fine  rootlets  of  the  plant  join  together 
to  form  the  large  roots,  or  of  the  rills  and  rivulets  that  flow  together 
to  form  the  large  streams  and  rivers.     In  structure,  the  veins  resem- 
ble the  arteries,  but  their  walls  are  comparatively  inelastic.     They 
are  more  numerous,  and  communicate  with  each  other  freely  in 
their  course,  by  means  of  interlacing  branches. 

37.  But  the  chief  point  of  distinction  is  in  the  presence  of  the 
valves  in  the  veins.     These  are  little  folds  of  membrane,  disposed 
in  such  a  way  that  they  open  only  to  receive  the  blood  flowing 
toward  the  heart,  and  close  against  a  current  in  the  opposite  direc- 
tion.    Their  position  in  the  veins  on  the  back  of  the  hand  may  be 
readily  observed,  if  we  first  obstruct  the 

return  of  blood  by  a  cord  tied  around  the 
forearm  or  wrist.  In  a  few  minutes  the 
veins  will  appear  swollen,  and  upon  them 
will  be  seen  certain  prominences,  about  an 
inch  apart.  These  latter  indicate  the  lo- 
cation of  the  valves,  or,  rather,  they  show  FIG.  38.— THE  VALVES  OF  THB 

,,       ,     ,,  ,        .         »  ,,     , .  ,  VEINS  HIGHLY  MAGNIFIED. 

that  the  vessels  in  front  of  the  valves  are 

distended  by  the  blood,  which  cannot  force  a  passage  back  through 

them. 

38.  This  simple  experiment  proves  that  the  true  direction  of  the 
venous  blood  is  toward  the  heart.     That  the  color  of  the  blood  is 
dark  will  be  evident,  if  we  compare  the  hand  thus  bound  by  a  cord 
with  the  hand  not  so  bound.     It  also  prdves  that  the  veins  lie  near 
the  surface,  while  the  arteries  are  beneath  the  muscles,  well  pro- 
six  times  ;  of  a  tapir,  forty-four  times  ;  of  a  horse,  forty  times ;  of  a  wolf, 
forty-five  times  ;  of  a  fox,  forty-three  times  ;  of  a  bear,  thirty-eight  times  ;  of 
a  monkey,  forty-eight  times  ;  of  an  eagle,  one  hundred  and  sixty  times.     It 
was  impossible  to  determine  the  beatings  of  the  elephant's  pulse.     A  butterfly, 
however,  it  was  discovered,  experienced  sixty  heart  pulsations  in  a  minute,'* 


36.  What  are  the  veins?    How  do  they  form  ?    What  do  they  resemble? 

37.  Valves  in  the  veins  ?    What  are  they  ?    Their  position  ?    Experiment  with  the  cord  ? 
88.  What  will  be  proved  by  the  experiment  ?    What  inference  is  drawn  f 


146 


THE   CIRCULATION. 


tected  from  pressure;  and  that  free  communication  exists  from  one 
vein  to  another.  If  now  we  test  the  temperature  of  the  constricted 
member  by  means  of  a  thermometer,  we  will  find  that  it  is  colder 
than  natural,  although  the  amount  of  blood  is  larger  than  usual. 
From  this  fact  we  infer,  that  whatever  impedes  the  venous  circula- 
tion tends  to  diminish  vitality ;  and  hence,  articles  of  clothing  or 
constrained  postures,  that  confine  the  body  or  limbs,  and  hinder  the 
circulation  of  the  blood,  are  to  be  avoided  as  injurious  to  the  health 
39.  The  Capillaries. — A  third  set  of  vessels  completes  the  list 
of  the  organs  of  circulation,  namely,  the  capillary  vessels,  so  called 
(from  the  Latin  word  capillaris,  hair-like),  because  of  their  extreme 
fineness.  They  are,  however,  smaller  than  any  hair,  having  a  diam- 
eter of  about  -jTjVjr  °f  an  inch,  and  can  only  be  observed  by  the  use 
of  the  microscope.  These  vessels  are  the  connecting  link  between 
the  last  of  the  arteries  and  the  first  of  the  veins.  The  existence  of 
these  vessels  was  unknown  to  Harvey,  and  was  the  one  step  want- 
ing to  complete  his  great  discovery.  The  capillaries  were  not  dis- 
covered until  1661,  a  short  time  after  the  invention  of  the  micro- 
scope. 


FIG.  39.— WEB  OP  A  FROG'S  FOOT; 
slightly  magnified. 


Pio.  40.— MARGIN  OF  FROG'S  WEB, 
magnified  thirty  diameters. 


40.  The  circulation  of  the  blood,  as  seen  under  the  microscope, 
in  the  transparent  web  of  a  frog's  foot,  is  a  beautiful  sight,  pos- 
sessing more  than  ordinary  interest,  from  the  fact  that  something 


39.  Capillaries?    How  regarded  ?    Harvey? 

40.  The  circulation  of  the  blood  in  the  web  of  a  frogs  foot  ?    Describe  it    How  general 
IB  Uie  existence  of  the  tissues  ? 


THE    CIRCULATION.  14? 

much  grander  is  taking  place  in  our  own  bodies.  It  is  like  opening 
a  secret  page  in  the  history  of  our  own  frames.  We  there  see  dis- 
tinctly the  three  classes  of  vessels  with  their  moving  contents ;  first, 
the  artery,  with  its  torrent  of  blood  rushing  down  from  the  heart; 
secondly,  the  vein,  with  its  slow,  steady  stream  flowing  in  the  oppo- 
site direction ;  and  between  them  lies  the  network  of  capillaries,  so 
fine  that  the  corpuscles  can  pass  through  only  "  in  single  file."  The 
current  of  the  capillaries  has  here  an  uncertain  or  swaying  motion, 
hurrying  first  in  one  direction,  then  hesitating,  and  turning  back  in 
the  opposite  direction,  and  sometimes  the  capillaries  contract  so  as 
to  be  entirely  empty.  Certain  of  the  tissues  are  destitute  of  capil- 
laries ;  such  are  cartilage,  hair,  and  a  few  others  on  the  exterior  of 
the  body.  In  all  other  structures,  networks  of  these  vessels  are 
spread  out  in  countless  numbers ;  so  abundant  is  the  supply,  that 
it  is  almost  impossible  to  puncture  any  part  with  the  point  of  a 
needle  without  lacerating  tens,  or  even  hundreds  of  these  vessels. 
(Read  Note  1 1. )  (See  Appendix,  page  307). 

41.  The  capillaries  are  elastic,  and  may  so  expand  as  to  pro- 
duce an  effect  visible  to  the  naked  eye.  If  a  grain  of  sand,  or 

11.  Course  of  the  Blood  in  the  Capillaries. — "The  phenomena  of 
the  capillary  circulation  are  only  observable  with  the  aid  of  the  microscope. 
It  was  not  granted  to  the  discoverer  of  the  circulation  to  see  the  blood  moving 
through  the  capillaries,  and  he  never  knew  the  exact  mode  of  communication 
between  the  arteries  and  veins.  After  it  was  pretty  generally  acknowledged 
that  the  blood  did  pass  from  the  arteries  to  the  veins,  it  was  disputed  whether 
it  passed  in  an  intermediate  system  of  vessels,  or  became  diffused  in  the  sub- 
stance of  the  tissues,  like  a  river  flowing  between  numberless  little  islands,  to 
be  collected  by  the  venous  radicles  and  conveyed  to  the  heart.  Accurate  mi- 
croscopic investigations  have  now  demonstrated  the  existence,  and  given  us  a 
clear  idea  of  the  anatomy  of  the  intermediate  vessels.  In  1661  the  celebrated 
anatomist  Malpighi  first  saw  the  movement  of  the  blood  in  the  capillaries,  in 
the  lungs  of  a  frog.  This  spectacle  has  ever  since  been  the  delight  of  the 
physiologist.  "We  see  the  great  arterial  rivers,  in  which  the  blood  flows  with 
wonderful  rapidity,  branching  and  subdividing,  until  the  blood  is  brought  to 
the  superb  network  of  fine  capillaries,  where  the  corpuscles  dart  along  one  by 
one,  the  fluid  then  being  collected  by  the  veins,  and  carried  in  great  currents 
to  the  heart.  "—Flint. 


41.  Elasticity  of  the  capillaries  T    Grain  of  sand  in  the  eye  ?    Blush  ?    Other  cases  ? 


148  THE    CIRCULATION. 

some  other  foreign  particle,  lodge  in  the  eye,  it  will  become  irritated, 
and  in  a  short  time  the  white  of  the  eye  will  be  "blood-shot." 
This  appearance  is  due  to  an  increase  in  the  size  of  these  vessels. 
A  blush  is  another  example  of  this,  but  the  excitement  comes 
through  the  nervous  system,  and  the  cause  is  some  transient  emo- 
tion, either  of  pleasure  or  pain.  Another  example  is  sometimes 
seen  in  purplish  faces  of  men  addicted  to  drinking  brandy ;  in  them 
the  condition  is  a  congestion  of  the  capillary  circulation,  and  is  per- 
manent, the  vessels  having  lost  their  power  of  elastic  contraction. 

42.  Rapidity  of  the  Circulation.— That  the  blood  moves  with 
great  rapidity  is  evident  from  the  almost  instant  effects  of  certain 
poisons,  as  prussic  acid,  which  act  through   the    blood.     Experi- 
ments upon  the  horse,  dog,  and  other  inferior  animals,  have  been 
made  to  measure  its  velocity.     If  a  substance  which  is  capable  of  a 
distinct  chemical  reaction  (as  potassium  ferrocyanide,  or  barium  ni- 
trate) be  introduced  into  a  vein  on  one  side  of  a  horse,  and  at  the 
end  of  twenty  or  thirty-two  seconds,  blood  be  taken  from  a  distant 
vein  on  the  other  side,  its  presence  may  be  detected.     In  man,  the 
blood  moves  with  greater  speed,  and  the  circuit  is  completed  in 
twenty-four  seconds. 

43.  What  length  of  time  is  required  for  all  the  blood  of  the 
body  to  make  a  complete  round  of  the  circulation  1     This  question 
cannot  be  answered  with  absolute  accuracy,  since  the  amount  of 
the  blood  is  subject  to  continual  variations.     But,  if  we  assume 
this  to  be  one-eighth  of  the  weight  of  the  body — about  eighteen 
pounds — it  will  be  sufficiently  correct  for  our  purpose.     Now  to 
complete  the  circuit,  this  blood  must  pass  once  through  the  left 
ventricle,  the  capacity  of  which  is  two  ounces.     Accordingly,  we 
find  that,  under  ordinary  circumstances,  all  the  blood  makes  one  com- 
plete rotation  every  two  minutes — passing  successively  through  the 
heart,  the  capillaries  of  the  lungs,  the  arteries,  the  capillaries  of  the 
extremities,  and  through  the  veins. 

44.  Assimilation. — The  crowning  act   of  the  circulation — the 
furnishing  of   supplies    to    the    different    parts  of   the  body — is 

42.  Show  what  time  is  required  for  a  given  portion  of  blood  to  travel  once  around  the 
body. 

43.  Time  required  for  all  the  blood  to  circulate  completely  around  ? 

44.  What  is  meant  by  assimilation  ?    What  can  you  say  of  its  use,  etc.  ?    Time  ? 


THE    CIRCULATION.  149 

effected  by  means  of  the  capillaries.  The  organs  have  been  wasted 
by  use ;  the  blood  has  been  enriched  by  the  products  of  digestion. 
Here,  within  the  meshes  of  the  capillary  network,  the  needy  tissues 
and  the  needed  nutriment  are  brought  together.  By  some  myste- 
rious chemistry,  each  tissue  selects  and  withdraws  from  the  blood 
the  materials  it  requires,  and  converts  them  into  a  substance  like 
itself.  This  conversion  of  lifeless  food  into  living  tissue  is  called 
assimilation.  The  process  probably  takes  place  at  all  times^  but 
the  period  especially  favorable  for  it  is  during  sleep.  Then  the 
circulation  is  slower,  and  more  regular,  and  most  of  the  functions 
are  at  rest.  The  body  is  then  like  some  trusty  ship,  which,  after  a 
long  voyage,  is  "hauled  up  for  repairs."  (Read  Note  12.) 

45.  Injuries  to  the  Blood-vessels. — It  is  important  for  us  to 
be  able  to  discriminate  between  an  artery  and  a  vein,  in  the  case  of 
a  wound,  and  if  we  remember  the  physiology  of  the  circulation  we 
may  readily  do  so.  For,  as  we  have  already  seen,  hemorrhage  from 
an  artery  is  much  more  dangerous  than  that  from  a  vein.  The 
latter  tends  to  cease  spontaneously  after  a  short  time.  The  arterial 
blood  flows  away  from  the  heart  with  considerable  force,  in  jets, 
and  its  color  is  bright  scarlet.  The  venous  blood  flows  toward  the 
heart  from  that  side  of  the  wound  furthest  from  the  heart,  its 
stream  being  continuous  and  sluggish ;  its  color  is  dark.  In  an 

12.  Assimilation  in  Repair. — "Most  animals  have  the  power  to  repair, 
to  a  greater  or  less  extent,  the  mutilations  they  undergo.  In  man,  if  the  s-kin 
is  torn  off,  a  new  skin  heals  over  the  injury,  and  a  broken  bone  is  caused  to 
re-unite  by  the  deposit  of  bone  tissue  between  the  fragments.  But  among  the 
lower  animals  this  power  is  carried  to  a  high  degree.  The  tail  of  a  lizard,  if 
cut  off,  will  quickly  form  anew,  although  of  a  complex  structure ;  and  spiders 
and  crabs  are  able  to  develop  new  claws  upon  the  stumps  of  broken  ones. 
Observations  made  on  salamanders,  or  water-lizards,  show  the  still  more 
remarkable  fact  that  the  eye  and  a  part  of  the  head  may  be  entirely  restored. 
Certain  kinds  of  earth-worms  can  reproduce  a  large  portion  of  their  bodies,  and 
any  fragment  of  the  hydra  is  able  to  restore  itself,  and  become  a  complete 
creature  after  its  kind.  Assimilation  is  especially  active  in  early  years,  while 
the  body  is  growing ;  for  this  reason,  among  others,  the  perfect  health  of 
children  requires  that  they  shall  give  a  greater  number  of  hours  to  sleep — 
deep,  regular,  and  undisturbed  sleep — than  is  needed  in  later  life. " — Milne 
Edwards. 


45.  What  is  stated  of  the  injuries  to  the  blood- vessels? 


150  THE   CIRCULATION. 

injury  to  an  artery,  pressure  should  be  made  between  the  heart 
and  the  wound,  while  in  the  case  of  a  vein  that  persistently 
bleeds,  it  should  be  made  upon  the  vessel  beyond  its  point  of 
injury. 

46.  Effects  of  Alcohol  upon  the  Heart.— The  first  symptoms 
after  a  moderate  dose  of  alcohol  is  an  increase  of  the  heart's  action, 
a  flushing  of  the  face,  a  sensation  of  warmth  within,  a  general  glow 
without,  and  some  other  appearances  of  increased  vitality.     The 
action  has  been  that  of  a  spur  or  goad.     It  has  caused  strength  to 
be  expended  instead  of  increasing  it,  and,  in  fact,  costs  the  system 
whatever  amount  of  force  is  necessary  to  expel  it;  so  that  there  is 
a  loss  of  strength,  and  not  a  gain. 

47.  The  late  "Dr.  Parkes  made  a  careful  study  of  the  amount  of 
strain  put  upon  the  heart  by  alcohol.     He  found  that  it  increased 
both  the  number  and  force  of  the  heart's  pulsations.     The  period 
of  rest  between  the  beats  is  reduced,  and,  consequently,  the  heart's 
nutrition  must  be  interfered  with.     He  estimates,  in  one  set  of  ex- 
periments, that  the  extra  work  of  the  heart,  induced  by  alcohol, 
was  equivalent  to  the  lifting  of  15.8  tons  one  foot  daily;  and  dur- 
ing two  days,  24  tons  in  excess  of  the  regular  work.     Another  ex- 
perimenter states  that  he  has  known  a  single  glass  of  liquor  to  cause 
8000  extra  heart-beats,  equivalent   to  the  unnecessary  lifting   of 
9  tons  the  distance  of  one  foot.     Estimated  in  another  way,  this 
amount  of  over-tax  of  the  heart  is  equal  to  that  which  takes  place, 
during  one  day,  in  a  person  having  a  fever  that  raises  the  pulse  six 
to  nine  beats  above  the  rate  of  health. 

48.  Alcohol  as  a  Fat  Producer. — Alcohol  is  said  to  diminish 
waste,  and  to  make  those  "  fleshy  "  who  use  it.     This  may  well  be 
the  case  in  those — and  the  proportion  is  not  small — who  are  ren- 
dered sluggish  and  sleepy  by  it.     The  fat  which  they  acquire  is  the 
fat  of  inaction.     If  we  may  judge  of  the  true  influence  of  alcohol 
by  experiments  on  the  lower  animals,  that  are  compelled  to  take  it 
pure,  we  will  not  grant  it  any  fattening  power. 

49.  There  is  a  certain  "fatty  degeneration"  in  man — the  result 
of  alcohol  drinking — that  is  very  disastrous,  namely,  a  deposit  of 

46.  How  does  alcohol  affect  the  heart's  action?          48.  How  does  alcohol  make  one  fleshy? 

47.  Give  Dr.  Parkea*  experiment.  49.  What  results? 


THE   CIRCULATION.  151 

fat  in  the  muscles  of  the  body.  This  is  destructive  or  weakening 
to  muscular  power,  and  when  it  evinces  itself  in  the  heart,  it  creates 
a  change  that  is  to  be  dreaded  as  sapping  the  strength  of  the  one 
particular  organ  that  should  be  strong  in  drinkers.  It  attacks  them 
at  a  vital  spot.  The  blood  also  undergoes  a  fatty  change  which 
greatly  impairs  its  work  of  nourishing  the  body. 

50.  Exhaustion  Due  to  Alcohol. — The  heart  does  not  become 
habituated  to  the  poison  nor  become  tolerant  of  it.     On  the  con- 
trary, it  is  set  moving,  with  this  abnormal  activity,  with  each  re- 
newal of  the  dose.     This  form  of  exertion  is  not  exercise,  it  is  over- 
work ;  it  is  not  strengthening,  it  is  exhausting.     Very  few  persons 
who  habitually  use  alcoholic  stimulants  are  aware  of  the  enormous 
strain  that  is  imposed  upon  the  heart,  although  to  those  who  studi- 
ously consider  the  matter  the  wonder  is  that  this  organ  is  not  more 
rapidly  worn  out  than  it  is.     If  it  were  not  for  the  fact  that  the 
heart  is  made  of  the  strongest  muscular  tissue  in  the  body,  it  would 
of  necessity  fail  from  overstrain  long  before  it  does. 

51.  The  condition  of  the  heart,  mentioned  in  the  last  section,  is 
known  to  physicians  as  "  fatty  heart,"  and  in  part  explains  why  it 
is  that  drunkards  are  so  little  able  to  withstand  the  attack  of  those 
diseases  which  are  attended  by  fever.     It  is  a  well  known  fact  that 
they  are  among  the  first  to  succumb  to  cholera  and  other  epidemic 
diseases.     Sunstroke  is  another  disorder  peculiarly  frequent  in  that 
class  of  persons ;  and  to  indicate  that  fact  some  physicians  apply 
the  term  "  drink-stroke  "  to  that  disease. 

52.  Action  of  Tobacco  on  the  Heart. — Tobacco  both  quickens 
and  enfeebles  the  heart.     In  some  of  those  who  habitually  use  it,  it 
gives  rise  to  a  throbbing  or  heaving  sensation  in  the  region  of  the 
heart,  an  exaggerated  kind  of  palpitation ;  at  times,  this  is  so  tumultu- 
ous that  the  patient  fears  lest  his  last  hour  has  come.    In  other  cases, 
there  is  a  weak  and  irregular  heart-beat,  caused  by  tobacco  poisoning. 
This  is  not  so  alarming  to  the  patient  as  the  condition  just  men- 
tioned, but  is  no  less  dangerous  and  much  less  easily  cured.     It  is 
apt  to  injure  a  man's  capacity  for  business  affairs,  being  repressive 
of  healthful  energy  and  exertion. 

49.  What  change  in  the  "blood  due  to  alcohol  ? 

50.  Does  the  heart  tolerate  alcohol  ?    Do  users  of  it  know  the  effects  ? 

§1.  Cau  they  withstand  fever?        5g,  Wha.^  two  noticeable  elects  from  tobacco? 


152 


THE  CIRCULATION. 

TABLE  OF  THE  PRINCIPAL  ARTERIES, 

CSKB  PLATE  OPPOSITE  PAGE  129.) 


The  Head, 


Oph-tlial'mic,  supplies  the  eye.  ^ 

External  Ca-rot'id  (  tA^'g**1*  supplies  the  tongue. 

gives  off  J  ^a'ci"alj  supplies  the  lower  part  of  the  face. 

"  '  (  Tem'po-ral,  supplies  the  upper  part  of  the  head  und  lace 

The  Trunk. 

The  A  or'ta,  arising  from  the  heart,  is  the  main  arterial  trunk. 

Cor'o-na-ry,  supplies  the  walls  of  the  heart 

Bron'cki-al,  supplies  the  lungs. 

In-ter-cos'tals,  supply  the  walls  of  the  chest. 

Gas'tric,  supplies  the  stomach. 

He-pat'ic,  supplies  the  liver. 

Splenic,  supplies  the  spleen. 

He'nal,  supplies  the  kidney. 

Mes-en-ter'ics,  supply  the  bowels. 

Spi'nal,  supplies  the  spinal  conl. 

The  Upper  Umb. 

Branches  of  the  Ax-il-la'ry,  supply  the  shoulder. 
"        Bra'cni-al,  supply  the  arm. 

"^  I  supply  the  forearm  and  fingers. 
UTnar,    ) 

The  Lower  Limb* 

Branches  of  the  Fem'o-ral,  supply  the  hip  and  thigh, 

"       Pop-li-te'al,  1 
w  <»        Tib'l-al,         >  supply  the  leg  and  foot. 

) 


THE  CIRCULATION.  153 


QUESTIONS    FOR    TOPICAL    REVIEW. 

PAGV 

1.  In  what  organisms  is  the  so-called  circulatory  fluid  found  ? 129 

2.  How  is  it  designated  in  the  different  organisms  ? 129 

3.  What  can  you  state  of  the  importance  of  blood  to  the  body  ? 129, 130 

4.  Of  its  great  abundance,  color,  and  composition? 129,130 

5.  Describe  the  corpuscles  of  the  human  blood 130, 131 

6 .  What  is  said  of  them  in  comparison  with  those  of  the  lower  animals  ? 131 

T.  Of  the  importance  of  sometimes  detecting  human  from  other  blood? 131 

8.  What  means  have  we  of  detecting  blood  in  spots  or  stains  ? 131 

9.  What  is  meant  by  coagulation  of  the  blood?. 132 

id  What  wisdom  is  there  in  the  law  of  the  blood's  coagulation  ? 182 

11.  How  is  this  wisdom  made  manifest? 182 

12.  In  what  cases  is  the  aid  of  the  surgeon  required? 132, 133 

13.  What  are  the  two  great  uses  of  the  blood  ? 133 

14.  Through  what  mediums  is  the  blood  provided  with  new  material  and  relieved  of  the 

old  material? 133 

15.  What  do  you  understand  by  the  operation  called  transfusion  ? 134 

16.  What  cases  of  transfusion  are  reported  of  the  lower  animals  ? 134. 

17.  What  can  you  state  of  transfusion  as  practiced  upon  man  ? 1X4 

18.  What  further  can  you  say  on  the  subject? IS* 

19.  What  changes  take  place  in  the  color  of  the  blood  in  its  journey  through  the  system  ?  1% 

20.  State  all  you  can  in  relation  to  the  circulation  of  the  blood , 136 

21.  All,  in  relation  to  the  size,  shape,  and  location  of  the  heart. 1S6 

22.  How  is  the  loss  of  power  in  the  heart-movements  obviated  ? 136 

23.  Give  a  description  of  the  formation  of  the  heart...., 1S7 

24.  What  can  you  state  of  the  ventricles  and  auricles  of  the  heart  ? 137 

25.  Describe  the  action  of  the  heart 137,138 

26.  What  special  vitality  does  the  tissue  of  the  heart  possess? 188 

27.  State  all  you  can  on  the  subject 138 

28.  Describe  the  course  of  the  blood  through  the  cavities  of  the  heart 139 

29.  Describe  the  mechanism  that  regulates  the  heart-currents 139 

30.  How  do  you  account  for  the  two  heart-sounds  at  the  front  of  the  chest  ? 139 

31.  State  what  you  can  of  the  frequency  of  the  heart's  action 139, 140 

32.  Of  the  activity  of  the  heart 141 

33.  What  do  you  understand  by  the  arteries?. , 143 

34.  State  what  you  can  of  the  arteries  and  the  arterial  system 143 

85.  What  do  you  understand  by  the  pulse?.... 143,144 

86.  In  what  part  of  the  body  may  the  pulse  be  felt? 144 

37.  What  further  can  you  state  or  the  pulse? .' 144 

3a  Whatare  the  veins? 145 

69.  Where  do  they  exist,  and  how  are  they  formed?. ,   .  145 

40.  Describe  the  valves  of  the  veins  and  their  uses 145 

41.  Now  give  a  full  description  of  the  construction  of  the  veins. 145 

42.  What  further  can  you  state  of  the  veins?. 145, 146 

43.  What  do  you  understand  by  the  capillaries?. 146,147 

44.  What  service  do  the  capillaries  perform  ? 146 

45.  What  can  you  state  of  the  rapidity  of  the  blood's  circulation  ? 148 

46.  Of  the  process  known  as  assimilation  ?. 149 

47.  Of  injuries  to  the  blood-vessels  ? 149 

48.  What  is  the  effect  of  alcohol  upon  the  heart?. 150 

49.  What  is  said  of  alcohol  as  &  fat-producer? ,.....,-......,.  15; 


CHAPTER    ^v  Ail. 

RESPIRATION. 

Th«  Objects  of  Respiration — The  Lungs — The  Air-passages — The  Movements  of 
Respiration — Expiration  and  Inspiration — The  Frequency  of  Respiration- 
Capacity  of  the  Lungs — The  Air  we  Breathe— Changes  in  the  Air  from 
Respiration — Changes  in  the  Blood — Interchange  of  Gases  in  the  Lungs- - 
Comparison  between  Arterial  and  Venous  Blood — Respiratory  Labor — Im- 
purities  of  the  Air — Dust — Carbonic  Acid — Effects  of  Impure  Air — Nature's 
Provision  for  Purifying  the  Air — Ventilation — Animal  Heat — Spontaneous 
Combustion. 

1.  The   Object  of  Respiration. — In  one  set  of  capillaries,  or 
hair-like  vessels,  the  blood  is  impoverished  in  order  to  support  the 
different  members  and-  organs  of  the  body.     In  another  capillary 
system  the  blood  is  refreshed  and  again  made  fit  to  sustain  life. 
The  former  belongs  to  the  greater  or  systemic  circulation ;  the  latter 
to  the  lesser  or  pulmonary,  so  called  from  pulmo,  the  lungs,  in  which 
organs  it  is  situated.     The  blood,  as  sent  from  the  right  side  of  the 
heart  to  the  lungs,  is  venous,  dark,  impure,  and  of  a  nature  hurtful 
to  the  tissues.     But,  when  the  blood  returns  from  the  lungs  to  the 
left  side  of  the  heart,  it  has  become  arterial,  bright,  pure,  and  no 
longer  injurious.     This  marvellous  purifying  change  is  effected  by 
means  of  the  very  familiar  act  of  respiration,  or  breathing. 

2.  The  Lungs. — The  lungs  are  the  special  organs  of  respiration. 
There  are  two  of  them,  one  on  each  side  of  the  chest,  which  cavity 
they,  with  the  heart,  almost  wholly  fill.    The  lung-substance  is  soft, 
elastic,  and  sponge-like.     Under  pressure  of  the  finger,  it  crepitates, 
or  crackles,  and  floats  when  thrown  into  water;  these  properties 
being  due  to  the  presence  of  air  in  the  minute  air-cells  of  the  lungs. 
To  facilitate  the  movements  necessary  to  these  organs,  each  of  them 

1.  Difference  between  the  two  sets  of  capillaries?     Change  effected  by  respiration  or 
breathing? 

2.  What  are  the  hmgs  1    How  many  lungs  are  there  ?    Lung-substance  ?    Its  properties  ? 
The  pleura  ? 


RESPIRATION. 


155 


is  provided  with  a  double  covering  of  an  exceedingly  smooth  and 
delicate  membrane,  called  the  pleura.     One  layer  of  the  pleura  is 


Fio.  41.— ORGANS  OF  THE  CHEST. 

A,  Lungs. 

B,  Heart. 


D,  Pulmonary  Artery. 

E,  Trachea. 


attached  to  the  walls  of  the  chest/  and  the  other  to  the  lungs ;  and 
they  glide,  one  upon  the  other,  with  utmost  freedom.  Like  the 
membrane  which  envelops  the  heart,  the  pleura  secretes  its  own 
lubricating  fluid,  in  quantities  sufficient  to  keep  it  always  moist. 

3.  The  Air-Passages. — The  lungs  communicate  with  the  exter- 
nal air  by  means  of  certain  air-tubes,  the  longest  of  which — the 
trachea ,  or  windpipe — runs  along  the  front  of  the  neck  (Fig.  41,  E, 
and  42).  Within  the  chest  this  tube  is  divided  into  two  branches, 
one  entering  each  lung;  these  in  turn  give  rise  to  numerous 
branches,  or  bronchial  tubes,  as  they  are  called,  which  gradually 
diminish  in  size  until  they  are  about  one  twenty-fifth  of  an  inch  in 

8.  Communication  of  the  lungs  with  the  external  air  ?    Bronchial  tabes \ 


156 


RESPIRATION. 


diameter.  Each  of  these  terminates  in  a  cluster  of  little  poshes, 
or  "  air-cells,"  having  very  thin  walls,  and  covered  with  a  capillary 
network,  the  most  intricate  in  the  body  (Fig  43). 

4.  These  tubes  are  somewhat  flexible,  sufficiently  so  to  bend 
when  the  parts  in  which  they  are  situated  move;  but  they  are 


Fio.  42.— LARYNX,  TRACHEA,  AND 
BRONCHIAL  TUBES. 


Pio.  43.— DIAGRAM  AND  SECTION  or 
THE  AIR-CELLS. 


greatly  strengthened  by  bands  or  rings  of  cartilage  which  keep  the 
passages  always  open;  otherwise  there  would  be  a  constantly- 
recurring  tendency  to  collapse  after  every  breath.  The  lung-sub- 
stance essentially  consists  of  these  bronchial  tubes  and  terminal 
air-cells,  with  the  blood-vessels  ramifying  about  them  (Fig.  44)r 
At  the  top  of  the  trachea  is  the  larynx,  a  sort  of  box  of  cartilage, 
across  which  are  stretched  the  vocal  cords.  Here  the  voice  is  pro- 
duced chiefly  by  the  passage  of  the  respired  air  over  these  cords, 
causing  them  to  vibrate. 

5.  Over  the  opening  of  the  larynx  is  found  the  epiglottis,  which 
fits  like  the  lid  of  a  box  at  the  entrance  to  the  lungs,  and  closes 
during  the  act  of  swallowing,  so  that  food  and  drink  shall  pass 


4.  Office  of  the  bronchial  tubes  ?    What  further  can  you  state  of  them  ? 

6.  The  epiglottis?    When  it  does  not  close  in  time,  what  is  the  consequence? 


RESPIRATION. 


backward  to  the  oesophagus,  or  gullet  (Fig.  45).  Occasionally  it 
does  not  close  in  time,  and  some  substance  intrudes  within  the 
larynx,  when  we  at  once  discover,  by  a  choking  sensation,  that 


Fia.  44,— SECTION  OF  THE  LUNOS. 


"something  has  gone  the  wrong  way,"  and,  by  coughing,  we 
attempt  to  expel  the  unwelcome  intruder.  The  epiglottis  is  one  of 
the  many  safeguards  furnished  by  nature  for  our  security  and  com- 
fort, and  is  planned  and  put  in  place  long  before  these  organs  are 
brought  into  actual  use  in  breathing  and  in  taking  food. 

6.  The  air-passages  are  lined  throughout  almost  their  whole  ex- 
tent with  mucous  membrane,  which  keeps  them  in  a  constantly 
moist  condition.  This  membrane  has  cells  of  a  peculiar  kind  upon 
its  outer  surface.  If  examined  under  a  powerful  microscope,  we  may 
see,  even  for  a  considerable  time  after  their  removal  from  the  body, 
that  these  cells  have  minute  hair-like  processes  in  motion,  which 
wave  like  a  field  of  grain  under  the  influence  of  a  breeze  (Fig.  46). 
This  is  a  truly  beautiful  sight ;  and  since  it  is  found  that  these 
little  cilia,  as  they  are  called,  always  produce  currents  in  one 

6.  Lining  of  the  air-passages?  Ciliated  cells?  Their  uses?  The  three  diseases  of  tha 
lungs? 


158 


RESPIRATION. 


direction — from  within  outward — it  is  probable  that  they  serve  a 
useful  purpose  in  catching  and  carrying  away  from  the  lungs  dust 
and  other  small  particles  drawn  in  with  the  breath  (Fig.  46).  The 


PIG.  45. --SECTION  OF  THE  MOUTH  AND  THROAT, 

A,  The  Tongue.  C,  Vocal  Cord.  N,  Trachea. 

B,  The  Uvula.  E,  Epiglottis.  O,  (Esophagus, 

L,  Larynx. 

three  diseases  which  more  commonly  affect  the  lungs,  as  the  result 
of  exposure,  are  pneumonia,  or  inflammation  of  the  lungs,  affecting, 
principally,  the  air-cells ;  bronchitis,  an  inflammation  of  the  large 
bronchial  tubes ;  and  pleurisy,  an  inflammation  of  the  pleura,  or 
outside  wrapping  of  the  lungs.  Among  the  young,  an  inflamma- 
tion of  the  trachea  takes  place,  known  as  croup. 

7.  The  Movements  of  Respiration. — The  act  of  breathing  haa 

7.  The  act  of  breathing?   Extension  of  the  chest  by  breathing  ? 


RESPIRATION.  159 

two  parts — (1),  inspiration,  or  drawing  air  into  the  lungs,  and  (2), 
expiration,  or  driving  it  out  again.  In  inspiration,  the  chest  ex- 
tends in  its  length,  breadth,  and  height.  The  motion  outward  and 
upward  can  be  observed  every  time  we 
draw  a  full  breath ;  and  is  caused  by 
a  lifting  of  the  ribs.  But  the  motion 
downward  is  not  so  apparent,  as  it  is 
caused  by  a  muscle  within  the  body 
called  the  diaphragm.  This  is  the  thin 
partition  which  separates  the  chest  from 
the  abdomen,  rising  like  a  dome  within  Fia  46. -CILIATED  CELLS  HIGHLY 

,  .  ._.  MAGNIFIED. 

the  chest  (Fig.  20). 

8.  With  every  inspiration  the  diaphragm  contracts,  and  in  so 
doing,  approaches  more  nearly  a  level  surface,  and  thus  enlarges  the 
capacity  of  the  chest.      Laughing,  sobbing,  and  sneezing  are  due  to 
sudden  action  of  the  diaphragm.      On  the   proper  acting  of  this 
muscle   depends  our  power  to  breathe   deeply;   and  like   other 
muscles,  its  strength  is  increased  by  exercise.      This  gives  that 
endurance,  or  "  long  wind,"  as  it  is  commonly  called,  which  is 
possessed  in  a  marked  degree  by  the  mountaineer,  the  oarsman,  and 
the  trained  singer.     The  habit  of  taking  frequent  and  deep  inspira- 
tions, in  the  erect  position,  with  the  shoulders  thrown  back,  tends 
greatly   to  increase    the    capacity  and   power  of    the   organs    of 
respiration. 

9.  Expiration  is  a  less  powerful  act  than  inspiration.      The  dia- 
phragm relaxes,  and  ascends  in  the  form  of  a  dome ;  the  ribs  descend 
and  contract  the  chest ;   while  the  lungs  themselves,  being  elastic, 
assist  to  drive  out  the  air.     The  latter  passes  out  through  the  same 
channels  by  which  it  entered.      At   the   end  of  each  expiration 
there  is  a  period  of  repose,  lasting  about  as  long  as  the  period  or 
action. 

10.  Frequency  of  Respiration. — It  is  usually  estimated  that  we 
breathe  once  during  every  four  beats  of  the  heart,  or  about  eighteen 
times  in  a  minute.    There  is,  of  course,  a  close  relation  between  the 

8.  Contraction  of  the  diaphragm?    Power  of  the  diaphragm?    Effects  of  extending  t1 1 
walls  of  the  chest  ?    The  habit  of  taking  frequent  and  deep  inspirations  ? 

9.  Expiration?    The  mechanism  of  expiration  ? 

10.  Frequency  of  respiration  2    Effect  of  hurried  action  of  the  heart  ? 


160  RESPIRATION. 

heart  and  lungs,  and  whatever  modifies  the  pulse,  in  like  man 
ner  affects  the  breathing.  When  the  action  of  the  heart  is  hurried, 
a  larger  amount  of  blood  is  sent  to  the  lungs,  and,  as  a  consequence, 
they  must  act  more  rapidly.  Occasionally,  the  heart  beats  so  very 
forcibly  that  the  lungs  cannot  keep  pace  with  it,  and  then  we  ex- 
perience  a  peculiar  sense  of  distress  from  the  want  of  air.  This 
takes  place  when  we  run  until  we  are  "  out  of  breath."  At  the  end 
of  every  fifth  or  sixth  breath,  the  inspiration  is  generally  longei 
than  usual,  the  effect  being  to  change  more  completely  the  air  of  the 
lungs. 

11.  Although,  as  a  general  rule,  the  work  of  respiration  goes  on 
unconsciously  and  without  exertion  on  our  part,  it  is,  nevertheless, 
under  the  control  of  the  wilL     We  can  increase  or  diminish  the 
frequency  of  its  acts  at  pleasure,  and  we  can  "  hold  the  breath,"  OP 
arrest  it  altogether  for  a  short  time.    From  twenty  to  thirty  seconds 
is  ordinarily  the  longest  period  in  which  the  breath  can  be  held ; 
but  if  we  first  expel  all  the  impure  air  from  the  lungs,  by  taking 
several  very  deep  inspirations,  the  time  may  be  extended  to  one  and  a 
half  or  even  two  minutes.      This  should  be  remembered,  and  acted 
upon,  before  passing  through  a  burning  building,  or  any  place  where 
the  air  is  very  foul     The  arrest  of  the  respiration  may  be  still 
further  prolonged  by  training  and  habit.      It  is  said  that  the  pearl- 
fishers  of  India  can  remain  three  or  four  minutes  under  water  with- 
out being  compelled  to  breathe. 

12.  Capacity  of  the  Lungs. — The  lungs  are  not  filled  and 
emptied  by  each  respiration.      For  while  their  full  capacity,  in  the 
adult,  is  three  hundred  and  twenty  cubic  inches,  or  more  than  a 
gallon,  the  ordinary  breathing  air  is  only  one-sixteenth  part  of  that 
volume,   or  twenty    cubic    inches — being  two-thirds  of    a  pint. 
Accordingly,  a  complete  renovation,  or  rotation,  of  the  air  of  the 
lungs  does  not  take  place  more  frequently  than  about  once  a  minute ; 
and  by  the  gradual  introduction  of  the  external  air,  its  temperature 
is  considerably  elevated  before  it  reaches  the  delicate  capillaries  that 
surround  the  air-cells.     In  tranquil  respiration,  less  than  two-thirds 


11.  Respiration  controlled  by  the  will  ?    Advantage  of  the  knowledge  to  us  ? 

12.  Capacity  of  the  lungs  ?    Time  required  to  renovate  the  air  iu  the  lungs  1    In  tranquil 
respiration  ?    Importance  of  the  provision  ? 


RESPIRATION  161 

of  the  breathing  power  is  called  into  exercise,  leaving  a  reserve 
capacity  of  about  one  hundred  and  twenty  cubic  inches,  equivalent 
to  three  and  one-half  pints.  This  provision  is  indispensable  to  the 
continuation  of  life ;  otherwise,  a  slight  interference  with  respira- 
tion— by  an  ordinary  cold,  for  instance — would  suffice  to  cut  off  the 
necessary  air,  and  the  spark  of  life  would  be  speedily  extinguished 
\  13.  The  Air  we  Breathe. — The  earth  is  enveloped  on  all  sides 

;  by  an  invisible  fluid,  called  the  atmosphere.  It  forms  a  vast  ocean 
of  air,  forty-five  miles  deep,  encircling  and  pervading  all  objects  on 
the  earth's  surface,  and  is  absolutely  essential  for  the  preservation 
\>  of  all  vegetable  and  animal  life — in  the  sea,  as  well  as  on  the  land 

.  and  in  the  air.  At  the  bottom,  or  in  the  lower  strata  of  this  ocean 
of  air,  we  move  and  have  our  being.  Perfectly  pure  water  will  not 
support  marine  life,  for  a  fish  may  be  drowned  in  water  from  which 
the  air  has  been  exhausted,  just  as  certainly  as  a  mouse,  or  any 
other  land  animal  will  perish  if  held  under  water  for  a  short  time. 
The  cause  is  the  same  in  both  cases — the  animal  is  deprived  of 
the  requisite  amount  of  air.  It  is  also  stated,  that  if  the  water- 
supply  of  the  plant  be  deprived  of  air,  its  growth  is  checked. 
(Read  Note  I.) 

1.  The  Atmosphere. — "  It  surrounds  us  on  all  sides,  yet  we  see  it  not; 
it  presses  on  us  with  a  load  of  fifteen  pounds  to  every  square  inch  of  surface  of 
our  bodies,  or  from  seventy  to  one  hundred  tons  on  us  in  all,  yet  we  do  not  so 
much  as  feel  its  weight  Softer  than  the  softest  down — more  impalpable  than 
the  finest  gossamer — it  leaves  the  cobweb  undisturbed,  and  scarcely  stirs  the 
lightest  flower  that  feeds  on  the  dew  it  supplies  ;  yet  it  bears  the  fleets  of 
nations  on  its  wings  around  the  world,  and  crushes  the  most  refractory  sub- 
stances beneath  its  weight.  When  in  motion,  its  force  is  sufficient  to  level  the 
most  stately  forests  with  the  earth  ;  to  raise  the  waters  of  the  ocean  into 
ridges  like  mountains,  and  dash  the  strongest  ships  to  pieces  like  toys.  It 
bends  the  rays  of  the  sun  from  their  path,  to  give  us  the  twilight  of  evening 
and  of  dawn ;  it  disperses  and  refracts  their  various  tints,  to  beautify  the  ap- 
proach and  retreat  of  the  orb  of  day.  But  for  the  atmosphere,  sunshine  would 
burst  on  us  and  fail  us  at  once,  and  at  once  remove  us  from  midnight  darkness 
to  the  blaze  of  noon.  We  should  have  no  twilight  to  soften  and  beautify  the 
landscape,  no  clouds  to  shade  us  from  the  scorching  heat ;  but  the  bald  earth, 
&3  it  revolved  on  its  axis,  would  turn  its  tanned  and  weakened  front  to  the  full 
and  unmitigated  rays  of  the  lord  of  day. " — Buish. 

13.  The  atmosphere?  How  high  or  deep?  How  essential  to  life?  Marine  life  iu  per- 
fectly pure  water  and  air  f 


162  RESPIRATION. 

14.  The  air  is  not  a  simple  element,  as  the  ancients  supposed, 
but  is  formed  by  the  mingling  of  two  gases,  known  to  the  chemist 
as  oxygen  and  nitrogen,  in  the  proportion  of  one  part  of  the  former 
to-  four  parts  of   the  latter.     These  gases  are  very  unlike,  being 
almost  opposite  in  their  properties:  nitrogen  is  weak,  inert,  and 
cannot  support  life;   while  oxygen  is  powerful,  and  incessantly 
active,  and  is  the  essential  element  which  gives  to  the  atmosphere 
its  power  to  support  life  and  combustion.     The  discovery  of  this 
fact  was  made  by  the  French  chemist,  Lavoisier,  in  1778. 

15.  Changes  in  the  Air  from  Respiration. — Air  that  has  been 
once  breathed  is  no-  longer  fit  for  respiration.     An  animal  confined 
within  it  will  soon  die ;  so,  also,  a  lighted  candle  placed  in  it  will 
be  at  once  extinguished.     If  we  collect  a  quantity  of  expired  air 
and  analyze  it,  we  shall  find  that  its  composition  is  not  the  same  as 
that  of  the  inspired  air.     When  the  air  entered  the  lungs  it  was 
rich  in  oxygen ;  now  it  contains  twenty-five  per  cent,  less  of  that 
gas.     Its  volume,  however,  remains  nearly  the  same — its  loss  being 
made  up  by  another  and  very  different  gas,  which  the  lungs  exhale, 
called  carbonic  acid,  or  as  the  chemist  terms  it,  carbonic  dioxide. 

16.  The  expired  air  has  also  gained  moisture.     This  is  noticed 
when  we  breathe  upon  a  mirror  or  the  window-pane,  the  surface 
being  tarnished  by  the  condensation  of  the  watery  vapor  given  off 
by  the  lungs.     In  cold  weather,  this  causes  the  fine  cloud  which  is 
Been  issuing  from  the  nostrils  or  mouth  with  each  expiration,  and 
contributes  in  forming  the  feathery  crystals  of  ice  which  decorate 
our  window-panes  on  a  winter's  morning. 

17.  This  watery  vapor  contains  a  variable  quantity  of  animal 
matter,  the  exact  nature  of  which  is  unknown ;  but  when  collected 
it  speedily  putrefies  and  becomes  highly  offensive.     From  the  effects, 
npon  small  animals,  of  confinement  in  their  own  exhalations,  having 
at  the  same  time  an  abundant,  supply  of  fresh  air,  it  is  believed  that 
the  organic  matters  thrown  off  by  the  lungs  and  skin  are  direct  an& 
active  poisons ;  and  that  to  such  emanations  from  the  body,  more 


14.  Composition  of  the  air?   Properties  of  the  two  gases  ? 

15.  Air  once  breathed?   An  animal  in  it?    A  candle?    Analysis  of  expired  air ?    Change 
In  volume? 

16.  What  else  has  the  expired  air  gained  ?   When  and  where  noticed? 

17.  Nature  of  the  watery  vapor?    Its  effects  upon  animals? 


RESPIRATION.  163 

than  to  any  other  cause,  are  due  the  depressing  and  even  fatal  re- 
sults which  follow  the  crowding  of  large  numbers  of  persons  into 
places  of  limited  capacity.  (Read  Note  2.) 

18.  History  furnishes  many  painful  instances  of  the  ill  effects  of 
overcrowding.  In  1756,  of  one  hundred  and  forty-six  Englishmen 
Imprisoned  in  the  Black  Hole  of  Calcutta,  only  twenty-three,  at  the 
end  of  eight  hours,  survived.  After  the  battle  of  Austerlitz,  three 
hundred  prisoners  were  crowded  into  a  cavern,  where,  in  a  few 
hours,  two-thirds  of  their  number  died.  On  board  a  steamship, 
during  a  stormy  night,  one  hundred  and  fifty  passengers  were-  con- 

2.  The  Two  Breaths. — "Every  time  you  breathe,  you  breathe  two  dif- 
ferent breaths  :  you  take  in  one,  you  give  out  another.  The  composition  of 
those  two  breaths  is  different  Their  effects  are  different.  The  breath  which 
has  been  breathed  out  must  not  be  breathed  in  again.  To  tell  you  why  it 
must  not  would  lead  me  into  anatomical  details,  not  quite  in  place  here  as  yet ; 
but  this  I  may  say  :  those  who  habitually  take  in  fresh  breath  will  probably 
grow  up  large,  strong,  ruddy,  cheerful,  active,  clear-headed — fit  for  their  work. 
Those  who  habitually  take  in  the  breath  which  has  been  breathed  out  by  them- 
selves, or  any  other  living  creature,  will  certainly  grow  up — if  they  grow  up  at 
all — small,  weak,  pale,  nervous,  depressed,  unfit  for  work,  and  tempted  contin- 
ually to  resort  to  stimulants  and  become  drunkards. 

"  If  you  want  to  see  how  different  the  breath  breathed  out  is  from  the 
breath  taken  in,  you  have  only  to  try  a  somewhat  cruel  experiment,  but  one 
which  people  too  often  try  upon  themselves,  their  children,  and  their  work- 
people. If  you  take  any  small  animal  with  lungs  like  your  own — a  mouse,  for 
instance— and  force  it  to  breathe  no  air  but  what  you  have  breathed  already ; 
if  you  put  it  in  a  close  box,  and,  while  you  take  in  breath  from  the  outer  air, 
send  out  your  breath  through  a  tube  into  that  box,  the  animal  will  soon  faint ; 
if  you  go  on  long  with  this  process,  he  will  die.  *  *  *  *  What  becomes  of 
this  breath  which  passes  from  your  lips  ?  Is  it  merely  harmful,  merely  waste  \ 
God  forbid  !  God  has  forbidden  that  anything  should  be  merely  harmful  or 
merely  waste  in  this  so  wise  and  well-made  world.  The  carbonic  acid  which 
passes  from  your  lips  at  every  breath  is  a  precious  boon  to  thousands  of  thinga 
of  which  you  have  daily  need.  For  though  you  must  not  breathe  your  breath 
again,  you  may  at  least  eat  your  breath,  if  you  will  allow  the  sun  to  transmute 
it  for  you  into  vegetables  ;  or  you  may  enjoy  its  fragrance  and  its  color  in  tha 
shape  of  a  lily  or  a  rose.  When  you  walk  in  a  sunlit  garden,  every  word  you 
speak,  every  breath  you  breathe,  is  feeding  the  plants  and  flowers  around."— 
llev.  Charles  Kingsley  on  the  Two  Breaths. 


18.  Give  some  of  the  instances  furnished  by  history. 


E 

Y\ 


164  RESPIRATION. 

fined  in  a  small  cabin,  but  when  morning  came,  only  eighty  remained 
alive. 

19.  Changes  in  the  Blood  from  Respiration. — The  most  strik- 
ing change  which  the  blood  undergoes  by  its  passage  through  the 
lungs,  is  the  change  of  color  from  a  dark  blue  to  bright  red.     That 
this  change  is  dependent  upon  respiration  has  been  fully  proved  by 
experiment.     If  the  trachea,  or  windpipe,  of  a  living  animal  be  so 
compressed  as  to  exclude  the  air  from  the  lungs,  the  blood  in  the 
arteries  will  gradually  grow  darker,  until  its  color  is  the  same  as 
that  of  the  venous  blood.     When  the   pressure   is  removed,  the 
blood  speedily  resumes  its  bright  hue.     Again,  if  an  animal  breathes 
an  atmosphere  containing  more  oxygen  than  atmospheric  air,  the 
color  changes  from  scarlet  to  vermilion,  and  becomes  even  brighter 
than  arterial  blood.     This  change  of  color  is  not  of  itself  a  very 
important  matter,  but  it  indicates  a  most  important  change  of  com- 
position.   (See  Appendix,  pages  306  ,/>8.) 

20.  The  air,  as  we  have  see**,  by  respiration  loses  oxygen  and 
gains  carbonic  acid :  the  blood,  on  the  contrary,  gains  oxygen  and 
loses  carbonic  acid.     Oxygen  is  the  food  of  the  blood  corpuscles ; 
while  the  articles  we  eat  and  drink  go  more  directly  to  the  plasma 
of  the  blood.     The  air,  then,  it  is  plain,  is  a  sort  of  food,  and  we 
should  undoubtedly  so  regard  it,  if  it  were  not  for  the  fact  that  we 
require  it  constantly,  instead  of  taking  it  at  stated  intervals,  as  is 
the  case  with  our  articles  of  diet.     Again,  as  the  demand  of  the 
system  for  food  is  expressed  by  the  sensation  of  hunger,  so  the  de- 
mand for  air  is  marked  by  a  painful  sensation  called  suffocation. 

21.  Interchange  of  Gases  in  the  Lungs.-^-But  the  air  and  the 
blood  are  not  in  contact,  as  they  are  separated  from  each  other  by 
ths  walls  of  the  air-cells  and  of  the  blood-vessels.     How  then  do 
the  two  gases,  oxygen  and  carbonic  acid,  exchange  places  ?     Moist 
animal  membranes  have  a  property  which  enables  them  to. transmit 
^ases   through  their   substance,  although   they  are  impervious  to 
liquids.     This  may  be  beautifully  shown  by  suspending  a  bladder 
containing  dark  venous  blood  in  a  jar  of  oxygen.     At  the  end  of  a 

19.  Change  in  the  blood  from  blue  to  red.    Upon  what  does  the  change  depend  ?    HOTH 
shown  ? 

20.  What  does  the  air  lose  and  gain  by  respiration  ?    What,  the  blood  ?    Air  as  food  ? 

21.  Moist  animal  membranes ?    How  shown  with  the  bladder? 


RESPIRATION  165 

few  hours  the  oxygen  will  have  diminished,  the  blood  will  be 
brighter  in  color,  and  carbonic  acid  will  be  found  in  the  jar. 

22.  If  this  interchange  take  place  outside  of  the  body,  it  must 
take  place  more  perfectly  within  it,  where  it  is  favored  by  many 
additional  circumstances.  The  walls  of  the  vessels  and  the  air-cells 
offer  no  obstacle  to  this  process,  which  is  known  as  gaseous  diffusion 
Both  parts  of  this  process  of  exchange  are  equally  important.  With- 
out oxygen  life  ceases ;  if  carbonic  acid  is  not  thrown  off,  it  acts 
like  a  poison,  producing  unconsciousness,  convulsions,  and  death. 
\/23.  Difference  between  Arterial  and  Venous  Blood.— The 
'following  table  presents  the  essential  points  of  difference  in  the  ap- 
pearance and  composition  of  the  blood,  before  and  after  its  passage 
through  the  lungs : 

Venous  Blood.  Arterial  Blooff. 

Color,  Dark  blue,  Scarlet 

Oxygen,  8  per  cent,*  18  per  cent. 

Carbonic  Acid,  15  to  20  per  cent,  6  per  cent,  or  less. 

Water,  More.  Less. 

The  temperature  of  the  blood  varies  considerably ;  but  the  arterial 
stream  is  generally  warmer  than  the  venous.  The  blood  imparts 
heat  to  the  air  while  passing  through  the  lungs,  and  consequently 
the  contents  of  the  right  side  of  the  heart  have  a  higher  tempera- 
ture than  the  contents  of  the  left  side.* 

24.  By  means  of  the  spectroscope,  we  learn  that  the  change  of 
color  in  the  blood  has  its  seat  in  the  corpuscles ;  and  that,  accord- 
ing as  they  retain  oxygen,  or  release  it,  they  present  the  spectrum  of 
arterial  or  of  venous  blood.  There  evidently  exists,  on  the  part  of 
these  little  bodies,  an  affinity  for  this  gas,  and  hence  they  have 
been  called  "  carriers  of  oxygen.'*  It  was  long  ago  thought  that 
blue  blood  was  peculiar  to  persons  of  princely  or  royal  descent,  and 
boastful  allusions  to  the  "  sang  azure  "  of  kings  and  nobles  are  quite 
often  met  with.  Physiology,  however,  informs  us  that  blue  blood 
flows  in  the  veins  of  all — the  low  as  well  as  the  high — and  that  so 
far  from  being  a  mark  of  purity,  it  really  indicates  waste  and  decay. 

*  "  Bernard  has  succeeded  in  establishing  the  following  facts  with  regard  to  the  tempera- 
ture (of  the  blood)  in  various  parts  of  the  circulatory  system  in  dogs  and  sheep :  1.  The 
blood  is  wanner  in  the  right  than  in  the  left  cavities  of  the  heart.  2.  It  is  warmer  in  the 
arteries  than  in  the  veins,  with  a  few  exceptions."— Physiology  of  Man,  Flint. 

22.  Gaseous  diffusion?    If  oxygen  be  not  received ?    If  carbonic  acid  be  retained? 

23.  Difference  in  the  appearance  and  composition  of  the  blood?     Temperature  of  the 
blood  ?    The  blood  while  passing  through  the  lungs  ?    The  consequence  ? 

24.  What  do  we  learn  by  means  of  the  spectroscope  1    "Carriers  of  oxygen"?    Blue 
t>u>od  in  the  system! 


166  BESPIKATIOIT. 

25.  Amount  of  Respiratory  Labor. — During  ordinary  calm 
respiration,  we  breathe  eighteen  times  in  a  minute;  and  twenty 
cubic  inches  of  air  pass  in  and  out  of  the  lungs  with  every  breath. 
This  is  equivalent  to  the  use  of  three  hundred  and  sixty  cubic 
inches,  or  more  than  ten  pints  of  air  each  minute.     From  this  we 
calculate  that  the  quantity  of  air  which  hourly  traverses  the  lungs 
is  about  thirteen  cubic  feet,  or  seventy-eight  gallons ;  and  daily,  not 
less  than  three  hundred  cubic  feet,  an  amount  nearly  equal  to  the 
contents  of  sixty  barrels. 

26.  Of  this  large  volume  of  air  five  per  cent,  is  absorbed  in  its 
transit   through  the   lungs.     The   loss   thus  sustained  is  almost 
wholly  of  oxygen,  and  amounts  to  fifteen  cubic  feet  daily.     The 
quantity  of  carbonic  acid  exhaled  by  the  lungs  during  the  day  is 
somewhat  less,  being  twelve  cubic  feet.     Under  the  influence  of 
excitement  or  exertion,  the  breathing  becomes  more  frequent  and 
more  profound;  and  then  the  internal  respiratory  work  increases  pro- 
portionately, and  may  even  be  double  that  of  the  above  estimate. 
It  has  been  estimated  that  in  drawing  a  full  breath,  a  man  exerts  a 
muscular  force  equal  to  raising  two  hundred  pounds  placed  upon 
the  chest. 

27.  Impurities  of  the  Air. — The  oxygen  in  the  atmosphere  is 
of  such  prime  importance,  and  its  proportion  is  so  nicely  adjusted 
to  the  wants  of  man,  that  any  gas  or  volatile  substance  which  sup- 
plants it  must  be  regarded  as  a  hurtful  impurity.     All  gases,  how- 
ever, are  not  alike  injurious.     Some,  if  inhaled,  are  necessarily 
fatal ;  arsenuretted  hydrogen  being  one  of  these,  a  single  bubble  of 
which  destroyed  the  life  of  its  discoverer,  Gehlen.     Others  are  not 
directly  dangerous,  but  because  they  take  the  place  of  oxygen,  and 
exclude  it  from  the  lungs,  they  do  harm,  and  become  dangerous. 
To  this  latter  class  belongs  carbonic  acid. 

28.  Most  of  the  actively  poisonous  gases  have  a  pungent  or 
offensive  odor ;  and,  as  may  be  inferred,  most  repugnant  odors  indi- 
cate the  presence  of  substances  unfit  for  respiration.     Accordingly, 
as  we  cannot  see  or  taste  these  impurities,  the  sense  of  smell  is  our 

25.  The  amount  of  air  that  passes  in  and  out  of  the  lungs  ? 

26.  Air  absorbed  in  its  transit  through  the  lungs?    The  loss?    Carbonic  acid  exhaled? 
Effect  of  excitement  or  exertion  ?    What  estimate  ? 

27.  Importance  of  the  oxygen  in  the  atmosphere  ?    Injurious  character  of  gases? 

28.  Pungency  of  gases?    The  inference  ?    Our  safeguard  2 


RESPIRATION.  167 

principal  safeguard  against  them.  In  this  we  recognize  the  fore- 
thought which  has  stationed  this  sense,  like  a  sentinel,  at  the  propel 
entrance  of  the  air-passages,  to  give  us  warning  of  approaching 
harm.  Take,  as  an  example,  the  ordinary  illuminating  gas  of 
cities,  from  which  so  many  accidents  happen.  How  many  more 
deaths  would  it  cause  if,  when  a  leak  occurs,  we  were  not  able  to 
discover  the  escape  of  the  gas  hy  means  of  its  disagreeable  odor. 
(Read  Notes  3  and  4. ) 

29.  Organic  matters  exist  in  increased  measure  in  the  expired 
breath  of  sick  persons,  and  impart  to  it,  at  times,  a  putrid  odor. 
This  is  especially  true  in  diseases  which,  like  typhus  and  scarlet 
fever,  are  referable  to  a  blood  poison.  In  such  cases  the  breath  is 
one  of  the  means  by  which  nature  seeks  to  expel  the  offending 
material  from  the  system.  Hence,  those  who  visit  or  nurse  fever- 
sick  persons  should  obey  the  oft-repeated  direction,  "  not  to  take 
the  breath  of  the  sick."  At  such  times,  if  ever,  fresh  air  is 
demanded,  not  alone  for  the  sick,  but  also  for  those  who  take  care 
of  them  (See  Care  of  Sick-Room,  Appendix). 

3.  Cleanliness  the  Sum  Total  of  Hygiene. — "Disinfectants  have 
the  power  of  destroying  the  cause,  and  of  arresting  the  spread  of  most  epi~ 
demies  and  contagious  diseases,  but  cleanliness   is  the   best  preventive  ol 
disease.     Whenever  practicable,  the  abundant  use  of  water  is  better  than 
disinfection.     'Let  no  one  ever  depend  upon  disinfectants,  fumigations,  and 
the  like,  for  purifying  the  air.     The  offensive   thing,  not  its  smell,  must 
be  removed.' " — Florence  Nightingale,  Notes  on  Nursing  (in part}. 

4.  The  True  Prevention  of  Epidemics. — "It  was  in  England  that 
solution  of  the  great  problem  of  hygiene  was  first  attempted.     *  Preventive 
Medicine,'  it  is  there  called.     Palmerston  told  a  deputation  which  waited  on 
him  in  order  to  ask  him  to  order  a  fast  on  the  approach  of  the  second  epidemic 
of  cholera,  to  cleanse  their  sewers,  and  diligently  visit  the  dwellings  of  the  poor. 
And  he  did  not  confine  himself  to  good  advice,  but,  with  his  usual  energy, 
he  laid  his  hand  on  sanitary  legislation,  and  purified  the  air  of  London  and 
the  large  manufacturing  towns.     The  result  of  the  sanitary  measures  carried 
out  was  a  reduction  of  the  mortality  of  London  from  26  to  23  per  1,000,  and 
in  some  of  the  towns  to  17  per  1,000 — a  low  death-rate  previously  only 
equalled  in  the  Isle  of  Wight.     More  than  four  thousand  lives  have  been  pro- 
served  yearly  in  London ;  and,  assuming  that  the  mortality  among  the  sick  is 
1  in  20,  this  number  represents  a  diminution  in  yearly  sickness  to  the  extent 
of  eighty  thousand." — Dr.  Joseph  Sceqen  in  the  Vienna  Medical  Weekly. 

29.  The  air  oi  rooms  m  wluch  lever-sick  persons  are  confined? 


168  RESPIRATION. 

30.  Dust  in  the  Air. — Attention  has  lately  been  directed  to  the 
dust,  or  haze,  that  marks  the  ray  of  sunshine  across  a  shaded  room. 
Just  as,  many  years  ago,  it  was  discovered  that  myriads  of  animal- 
cules were  found  in  the  water  we  drank,  so  now  the  microscope-  re- 
veals "  the  gay  motes  that  dance  along  a  sunbeam "  to  contain 
multitudes  of  animal  and  vegetable  forms  of  a  very  low  grade — the 
germs  of  fermentation  and  decay,  and   the   probable   sources  of 
disease. 

31.  It  is  found  that  the  best  filter  by  which  to  separate  this  float- 
ing dust  from  the  air  is  cotton  wool,  although  a  handkerchief  will 
imperfectly  answer  the  same  purpose.     In  a  lecture  on  this  subject 
by  Prof.  Tyndall,  he  remarks  that,  "by  breathing  through  a  cotton 
wool  respirator,  the  noxious  air  of  the  sick-room  is  restored  to  prac- 
tical purity.     Thus  filtered,  attendants   may  breathe  the  air  un- 
harmed.    In  all  probability,  the  protection  of  the  lungs  will  be  the 
protection  of  the  whole  system.     For  it  is  exceedingly  probable 
that  the  germs  which  lodge  in  the  air-passages  are  those  which  sow 
epidemic  disease  in  the  body.     If  this  be  so,  then  disease  can  cer- 
tainly be  warded  off  by  filters  of  cotton  wool-     By  this  means,  so 
far  as  the  germs  are  concerned,  the  air  of  the  highest  Alps  may  be 
brought  into  the  chamber  of  the  invalid." 

V  <^52*  Carbonic  Acid  in  the  Air. — We  have  already  spoken  of 
\  , V  this  gas  as  an  exhalation  from  the  lungs,  and  a  source  of  impurity ; 
but  it  exists  naturally  in  the  atmosphere  in  the  proportion  of  one- 
>iialf  part  per  thousand.  In  volcanic  regions  it  is  poured  forth  in 
enormous  quantities  from  fissures  in  the  earth's  surface.  Being 
heavier  than  air,  it  sometimes  settles  into  caves  and  hollows  in 
the  surface.  It  is  stated  that  in  the  island  of  Java,  there  is  a  place 
called  the  "  Valley  of  Poison,"  where  the  ground  is  covered  with 
the  bones  of  birds,  tigers,  and  other  wild  animals,  which  were  suffo- 
cated by  carbonic  acid  while  passing  over  it.  The  Lake  Avernus, 
the  fabled  entrance  to  the  infernal  regions,  was,  as  its  name  implies, 
birdless,  because  the  birds,  while  flying  over  it,  were  poisoned  by 
the  gas,  and  fell  dead  into  its  waters.  In  mines,  carbonic  acid 


80.  Animalcules  in  the  water?    Dust  in  the  air  ? 

81.  The  best  air  filter?    The  remarks  of  Prof.  Tyndall  ? 

82.  Carbonic  acid  in  volcanic  regions ?    In  Java  ?    At  Lake  Avernus?    In  mines? 


RESPIRATION.  169 

forms  the  dreaded  choke-damp,  while  carbureted  hydrogen  is  the 
fire-damp. 

33.  In  the  open  air,  men  seldom  suffer  from  carbonic  acid,  for, 
as  we  shall  see  presently,  nature  provides  for  its  rapid  distribution, 
and  even  turns  it  to  a  good  use.     But  its  ill  effects  are  painfully 
evident  in  our  homes,  schools,  and  churches,  where  it  is  liable  to 
collect  as  the  waste  product  of  respiration,  and  of  that  combustion 
which  is  necessary  for  lighting  and  warming  our  homes.     A  man 
exhales,  during  repose,  not  less  than  one-half  cubic  foot  of  carbonic 
acid  per  hour.     A  single  gas-burner  liberates  five  cubic  feet  in  the 
same  time,  therefore  spoiling  about  as  much  air  as  ten  men.     A  fire 
burning  in  a  grate  or  stove  emits  some  impure  gases,  and  at  the 
same  time  abstracts  from  the  air  as  much  oxygen  as  twelve  men 
would  consume  in  the  same  period,  thus  increasing  the  relative 
amount  of  carbonic  acid  in  the  air.     From  furnaces,  as  ordinarily 
constructed,  this  and  other  gases  are  constantly  leaking  and  poison- 
ing the  air  of  tightly-closed  apartments. 

34.  Effects  of  Impure  Air. — Carbonic  acid,  in  its  pure  form,  is 
irrespirable,  causing  rapid  death  by  suffocation.     Air  containing 
forty  parts  per  thousand  of  this  gas  (the  composition  of  the  expired 
breath)  extinguishes  a  lighted  candle,  and  is  fatal  to  birds  ;   when 
containing  one  hundred  parts,  it  no  longer  yields  oxygen  to  man  and 
other  warm-blooded  animals,  and   is,  of  course,  speedily  fatal  to 
them.     In  smaller  quantities,  this  gas  causes  headache,  labored  res- 
piration, palpitation,  unconsciousness,  and  convulsions. 

35.  In  crowded  and  badly  ventilated  apartments,  the  air  is 
breathed  over  until  it  contains  from  six  to  ten  times  the  natural 
amount  of  carbonic  acid.      This  contaminated  air  causes  dullness, 
drowsiness,  and  faintness,  because  the  dark,  impure  blood  circulates 
through  the  brain,  oppressing  that  organ,  and  causing  it  to  act  like  a 
blunted  tool.      This  is  a  condition  not  uncommon  in  our  schools, 
churches,  and  court-rooms — the  places  of  all  others  where  it  is  desir- 
able that  the  mind  should  be  alert  and  free  to  act ;  but,  unhappily, 


33.  In  the  open  air?    Amount  of  carbonic  acid  exhaled  by  a  man?    A  gas-burner t    A 
worn  fire  ?    From  furnaces  ? 

34.  Effects  of  inhaling  carbonic  acid  alone?   In  small  quantities? 

35.  Effects  of  the  air  in  crowded  and  badly- ventilated  rooms? 

8 


170  RESPIRATION. 

an  unseen  physiological  cause  is  at  work,  dispensing  weariness  and 
stupor  ,over  pupils,  audience,  and  juries.    (Read  Notes  5 


6.  The  Ground-  Atmosphere  and  its  Relations  to  Dwellings.  — 
"  The  soil,  which  naturally  contains  wholesome  air,  and  gives  facility  to  its 
every  movement,  is  not  less  permeable  by  poisonous  gases,  which  are  often 
found  to  pervade  and  issue  from  it  It  is  easy  to  find  illustrations  of  the  fact 
that  people  are  poisoned  through  the  ground,  since  it  is  almost  a  daily  occur- 
rence. Here  is  one,  related  by  an  eminent  authority,  von  Pettenkofer  :  —  '  In 
ft  residence  at  Augsburg,  apparently  endowed  with  every  qualification  for  health 
and  comfort,  several  priests  lived  together.  On  a  certain  morning,  one  of 
these,  not  the  least  zealous  and  prompt  in  the  performance  of  his  duties,  was 
missed  from  his  usual  post  at  the  matin  service.  His  colleagues  hurried  back 
to  their  common  dwelling  in  search  of  the  missing  priest,  and  found  him  lying 
prostrate  and  insensible  upon  the  floor  of  his  bed-chamber.  A  doctor  was 
immediately  called  in,  and  at  the  first  sight  of  his  patient,  declared  him  to  bo 
suffering  from  an  attack  of  typhus  fever.  The  Sisters  of  Charity,  upon  whom 
devolved  the  duty  of  nursing  him,  and  those  clerical  associates  who  were 
active  in  their  sympathy  and  prompt  to  visit  him  and  give  assistance,  were,  a 
few  hours  after,  attacked  in  the  same  way.  The  doctor  did  not  hesitate  in  his 
diagnosis,  and  pronounced  the  additional  cases  also  typhus  fever.  A  general 
alarm  prevailed  in  the  city,  and  many  called  at  the  house  of  the  priest,  who 
was  greatly  beloved.  Among  others  was  an  old  woman,  who  discovered  a 
strong  smell  of  gas,  and  believing  this  to  be  the  cause  of  the  sickness,  obtained 
permission  to  remove  the  priest  to  her  own  house.  The  priest  had  no  sooner 
breathed  the  fresh  air  than  he  began  to  revive,  and  during  the  very  first  evening 
of  his  removal  to  the  new  abode  he  became  so  much  better  as  to  make  an  im- 
portunate demand  for  food.  He  soon  got  entirely  well.  The  old  woman,  thus 
confirmed  in  her  gas  theory,  and  eager  to  save  the  remaining  patients,  who  had 
continued  to  increase  in  number  in  the  priests'  house,  now  had  an  interview 
with  the  manager  of  the  gas-works  which  supplied  the  town,  and  prevailed 
upon  him  to  investigate  the  condition  of  the  gas-pipes  in  the  vicinity  of  the 
priests'  residence.  This  was  done,  and  a  leak  from  which  the  gas  was  escaping 
into  the  ground  was  found  and  stopped.  The  air  of  the  house  was  perceived 
at  once  to  improve,  and  with  it  the  health  of  the  patients  that  were  not  re- 
moved ;  these  finally  completely  recovered  from  what  the  doctor  even  was 
compelled  to  admit  was  not  typhus  fever,  but  poisoning  by  gas.1  "  —  The  Book 
of  Health. 

6.  Pure  Air  and  Good  Morals.—"  Cleanliness  and  self-respect  go  to- 
gether, and  it  is  no  paradox  to  affirm  that  you  tend  to  purify  men's  thoughts 
and  feelings  when  you  purify  the  air  they  breathe.  With  a  low 

average  of  popular  health  you  will  have  a  low  average  of  national  morality,. 
and  probably  also  of  national  intellect.  Drunkenness  and  vice  of  other  kinds 


RESPIRATION.  171 

36.  -Another  unmistakable  result  of  living  in  and  breathing  foul 
air  is  found  in  certain  diseases  of  the  lungs,  especially  consumption. 
For  many  years  the  barracks  of  the  British  army  were  constructed 
without  any   regard  to  ventilation;   and  during  those   years  the 
statistics  showed  that  consumption  was  the  cause  of  a  very  large 
proportion  of  deaths.    At  last  the  government  began  to  improve  the 
condition  of  the  buildings,  giving  larger  space  and  air-supply ;  and 
as  a  consequence,  the  mortality  from  consumption  has  diminished 
more  than  one-third. 

37.  The  lower  animals   confined  in  the  impure  atmosphere  of 
menageries,  contract  the   same  diseases   as   man.     Those  brought 
from  a  tropical  climate,  and  requiring  to  be  closely  housed,  generally 
die  of  consumption.    In  the  Zoological  Gardens  of  Paris,  this  disease 
affected  nearly  all  monkeys,   until   care   was   taken  to   introduce 
fresh  air  by  ventilation,    and  then  it  almost  wholly  disappeared. 
The  tendency  of  certain  occupations  to  shorten  life  is  well  known, 
disease  being  occasioned  by  the  fumes  and  dust  which  arise  from 
the  materials  employed,  in  addition  to  the  bad  air  of  the  workshop 
or  factory,  where  many  hours  are  passed  daily.    (Read  Note  7. ) 

will  flourish  in  such  a  soil,  and  you  cannot  get  healthy  brains  to  grow  on  un- 
healthy bodies." — Lord  Derby. 

7.  Consumption  is  Lung  Starvation. — "The  practice  of  allowing  the 
lungs  only  improper  food,  in  the  form  of  vitiated  air,  is  one  of  the  most  preva- 
lent habits  of  civilized  life,  and  diseases  of  the  lungs  are  its  greatest  bane  and 
greatest  dread.  More  persons  die  by  consumption  than  by  any  other  single 
disease.  If  there  be  added  to  those  the  large  number  that  perish  every  year  by 
inflammation  of  the  lungs  and  bronchial  tubes,  disease  and  premature  death 
may  be  well  said  to  have  in  these  organs  their  chief  citadel.  The  leading 
cause  of  all  this  is,  undoubtedly,  the  poor  quality  of  the  food  on  which  the 
lungs  are  nurtured.  The  very  best  physicians,  when  their  attention  is 
directed  to  the  subject,  admit  the  full  force  of  this  conclusion,  and  that  it  has 
not  received  the  attention  it  deserves.  Professor  Hartshorne  remarks  on  this 
point,  that  'the  influence  of  impure  air  in  promoting  consumption  has 
probably  heretofore  been  underrated.'  '  The  vitiated  air  of  the  European  bar- 
rack system  for  soldiers,'  says  Professor  Parkes,  '  is  the  only  way  in  which  the 
great  prevalence  of  consumption  in  European  armies  can  be  accounted  for.' 
This  is  the  conclusion  to  which  the  Sanitary  Commissioners  for  the  army  came, 


86.  A  cause  of  consumption  ?    How  was  the  fact  illustrated  ? 

87.  How,  in  the  case  of  the  lower  animals  ?    Tendency  of  certain  occupations? 


172  RESPIRATION. 

38.  The  following  table  shows  the  comparative  amount  of  car- 
bonic acid  in  the  air  under  different  conditions,  and  the  effects 
sometimes  produced: — 

PROPORTION  OP  CARBONIC  ACIH  In  1000  parts  of  Air 

Air  of  country c 4 

Air  of  city .5 

In  hospital,  well  ventilated 6 

In  school,  church,  etc.,  fairly  ventilated 1. 2  to    2.5 

In  court-house,  factory,  etc. ,  without  ventilation .       4.    to  40. 

In  bed-room,  before  being  aired 4.5 

In  bed-room,  after  being  aired 1.5 

Constantly  breathed,  causing  ill  health 2. 

Occasionally  breathed,  causing  discomfort 8. 

Occasionally  breathed,  causing  distress 10. 

Expired  air 40. 

Air  no  longer  yielding  oxygen 100. 

39.  Nature's  Provision  fop  Purifying  the  Air. — We  have  seen 

that  carbonic  acid  is  heavier  than  air,  and  irrespirable.  Why,  then, 
does  it  not  sink  upon  and  overwhelm  mankind  with  a  silent,  invisi- 

in  their  celebrated  report :  '  A  great  amount  of  phthisis  (consumption)  has 
prevailed  in  the  most  varied  stations  of  the  army  and  in  the  most  beautiful 
climates — in  Gibraltar,  Malta,  Ionia,  Jamaica,  Trinidad,  Bermuda,  etc. — in  all 
of  which  places  the  only  common  condition  was  the  vitiated  atmosphere  which 
our  barrack  system  everywhere  produced.  And,  as  if  to  clinch  the  argument, 
there  has  been  of  late  years  a  most  decided  decline  in  phthisis  in  these  stations, 
while  the  only  circumstance  which  has  notably  changed  in  the  time  has  been 
the  condition  of  the  air.'  A  very  eminent  authority,  the  late  Dr.  Marshall 
Hall,  of  England,  said,  in  reference  to  pure  air  in  the  treatment  of  consump- 
tion, '  If  I  were  seriously  ill  of  consumption,  I  would  live  out  doors  day  and 
night,  except  in  rainy  weather,  or  midwinter  ;  then.  I  would  sleep  in  an  un- 
plastered  log  house.  Physic  has  no  nutriment,  gaspings  for  air  cannot  cure 
you,  monkey  capers  in  a  gymnasium  cannot  cure  you,  and  stimulants  cannot 
cure  you.  What  consumptives  want  is  pure  air,  not  physic — pure  air,  not 
medicated  air — plenty  of  meat  and  bread. '  Let  it  be  remembered,  in  this  con- 
nection, that  every  hygienic  or  health-promoting  measure  which  tends  to  cure 
a  disease  is  much  more  efficacious  in  preventing  it." — Black's  Ten  Laws  oj 
Health.  

38.  Give  the  fact  as  set  forth  in  the  table  ? 

39.  What  can  you  state  of  the  diffusive  power  of  gases  ?    The  added  influence  of  the 
winds? 


RESPIRATION.  173 

ble  wave  of  death  ?  Among  the  gases  there  is  a  more  potent  force 
than  gravity,  which  forever  prevents  such  a  tragedy.  It  is  known 
as  the  diffusive  power  of  gases.  It  acts  according  to  a  definite  law, 
and  with  a  resistless  energy  compelling  these  gases,  when  in  contact, 
to  mingle  until  they  are  thoroughly  diffused.  The  added  influence 
of  the  winds  is  useful,  by  insuring  more  rapid  changes  in  the  air, 
air  in  motion  being  perfectly  wholesome.  The  rains  also  wash 
the  air. 

40.  We  have  seen  that  the  whole  animal  creation  is  constantly 
taking  oxygen  from  the  atmosphere,  and  as  constantly  adding  to  it 
Vcast  volumes  of  gas,  that  is  prejudicial  to  the  normal  perform- 
ance of  animal  respiration.  How,  then,  does  the  air  retain,  un- 
changed, its  life-giving  properties  ?  The  uniform  purity  of  the  an 
is  secured  by  means  of  the  vegetable  creation.  Carbonic  acid  is  the 
food  of  the  plant,  and  oxygen  is  its  waste  product.  The  leaves  are 
its  lungs,  and  under  the  stimulus  of  sunlight  a  vegetable  respiration 
is  set  in  motion,  the  effects  of  which  are  just  the  reverse  of  that  of 
animals.  Thus  nature  purifies  the  air,  and  at  the  same  time  builds 
up  beautiful  and  useful  worlds — the  life  of  each  growing  out  of  the 
decay  of  the  other.  (Read  Note  8.) 

8.  Plants  and  the  Air. — "  Though  the  air  is  dependent  for  the  renewal  of 
its  oxygen  on  the  action  of  the  green  leaves  of  plants,  it  must  not  be  forgotten 
that  it  is  only  in  the  presence  and  under  the  stimulus  of  light  that  these  organ- 
isms decompose  carbonic  acid.  All  plants,  irrespective  of  their  kind  or  nature, 
absorb  oxygen  and  exhale  carbonic  acid  in  the  dark.  The  quantity  of  noxious 
gas  thus  eliminated  is,  however,  exceedingly  small  when  compared  with  the 
oxygen  thrown  out  during  the  day.  Aside  from  the  highly  deleterious  action 
that  plants  may  exert  on  the  atmosphere  of  a  sleeping-room,  by  increasing  the 
proportion  of  carbonic  aciJ  during  the  night,  there  is  another  and  more 
important  objection  to  be  urgud  against  their  presence  in  such  apartments. 
Like  animals,  they  exhale  peculiar  volatile  organic  principles,  which  in  many 
instances  render  the  air  unfit  for  the  purposes  of  respiration.  Even  in  the  daya 
of  Andronicus  this  fact  was  recognized,  for  he  says,  in  speaking  of  Arabia 
Felix,  that  '  by  reason  of  myrrh,  frankincense,  and  hot  spices  there  growing, 
the  air  was  so  obnoxious  to  their  brains,  that  the  very  inhabitants  at  some 
times  cannot  avoid  its  influence,'  What  the  influence  on  the  brains  of  the 
inhabitants  may  have  been  does  not  at  present  interest  us ;  we  have  only 


40.  How  is  the  constant  purity  of  the  air  secured  ?    Explain  the  process  ? 


174 


RESPIRATION. 


41.  In  the  sea,  as  in  the  air,  the  same  circle  of  changes  is  observed. 
Marino  animals  consume  oxygen  and  give  off  carbonic  acid,  while 
marine  plants  consume  carbonic  acid,  and  liberate  oxygen.     Taking 
advantage  of  this  fact,  we  may  so  arrange  aquaria  with  fishes  and 
sea-plants,  in  their  proper  combinations,  that  each  may  supply  the 
needs  of  the  other,  and  the  water  may  seldom  require  to  be  renewed. 
This  affords  us,  on  a  small  scale,  an  illustration  of  the  grand  circle 
of  changes  taking  place  in  the  air  about  us,  and  also  of  the  harmo- 
nious dependence  of  the  two  great  kingdoms  of  nature. 

42.  Ventilation. — Since  the  external  atmosphere,  as  provided  by 
nature,  is  always  pure,  and  since  the  air  in  our  dwellings  and  other 
buildings  is  almost  always  impure,  it  becomes  imperative  that  there 
should  be  a  free  communication  from  the  one  to  the  other.    This  we 
aim  to  accomplish  by  ventilation.      As  our  houses  are  ordinarily 
constructed,  the  theory  of  ventilation,  "  to  make  the  internal  as  pure 
as  the  external  air,"  is  seldom  carried  out.      Doors,  windows,  and 
flues,  the  natural  means  of  replenishing  the  air,  are  too  often  closed, 
almost  hermetically,  against  the  precious  element.      Special  means, 
or  special  attention,  must  therefore  be  used  to  secure  even  a  fair 
supply  of  fresh  air.    This  is  still  more  true  of  those  places  of  public 
resort,  where  large  numbers  of  persons  are  crowded  together.     (See 
Drainage,  Appendix.) 

43e  If  there  are  two  openings  in  a  room,  one  as  a  vent  for  foul 
air,  and  the  other  an  inlet  for  atmospheric  air,  and  if  the  openings 
be  large  in  proportion  to  the  number  of  air  consumers,  the  principal 
object  will  be  attained.  Thus,  a  door  and  window,  each  opening 
into  the  outer  air,  will  ordinarily  ventilate  a  small  apartment ;  or  a 
window  alone  will  answer,  if  it  be  open  both  above  and  below,  and 


quoted  the  statement  to  show  that  long  ago  the  emanations  from  plants  were 
regarded  as  having  an  influence  on  the  condition  of  the  air ;  and,  in  view 
of  our  present  ignorance,  it  would  be  wise  to  banish  them  from  our  sleeping 
apartments,  at  least  until  we  are  better  informed  regarding  their  true  proper- 
ties.*'— Draper  on  Poisoned  Air. 


41.  What  process  occurs  in  the  sea?    How  is  the  fact  illustrated  ? 

42.  Character  of  the  external  air?    Of  the  air  in  our  dwellings  ?    What  becomes  impera 
tive  ?    Imperfect  ventilation  of  our  dwellings  ? 

43.  What  hints  are  given  for  the  ventilation  of  our  dwellings  ? 


RESPIRATION. 


175 


the  open  space  at  each  end  be  not  less  than  one  inch  for  each  occu- 
pant of  the  room,  when  the  window  is  about  a  yard  wide.  The 
direction  of  the  current  is  generally  from  below  upward,  since  the 
foul,  heated  air  tends  to  rise ;  but  this  is  not  essential.*/  Its  rate 
need  not  be  rapid ;  a  "  draught,"  or  perceptible  current,  is  never 
necessary  to  good  ventilation.  The  temperature  of  the  air  admitted 
may  be  warm  or  cold.  It  is  thought  by  many  that  if  the  air  is 
cold,  it  is  pure ;  but  this  is  an  error,  since  cold  air  will  receive  and 
retain  the  same  impurities  as  warm  air. 

44.  Shall  we  open  our  bed-rooms  to  the  night  air  ?    Florence 
'          Nightingale  says,  in  effect,  that  night  air  is  the  only  air  we  can 
\then  breathe.     "  The  choice  is  between  pure  air  without  and  im- 
'pure  air  within.     Most 
people    prefer    the    lat- 
ter —  an    unaccountable 
choice.      An   open  win- 
dow, most  nights  in  the 
year,    can   hurt  no  one. 
In  great  cities,  night  air 
is  the  best  and  purest  to 
be   had  in   twenty-four 
hours.      I   could   better 

*  "When  the  window  is  of 
the  common  sash  kind,  a 
good  supply  of  fresh  air 
may  be  obtained  without  a 
current,  by  placing  a  strip 
of  board  about  four  inches 
wide  under  the  lower  sash 
(Fig.  47).  The  window  is 
thus  closed  against  rain  and 
snow,  but  allows  of  a  supply 
of  fresh  air  to  enter  between 
the  sashes.  If  still  more 
ventilation  is  needed  to  keep 

the  air  of  the  room  sweet,  the  same  arrangement  may  be  made  at  the  top  of 
the  window. 


FIG.  47. — Showing  manner  of  ventilating  by  in- 
serting strip  of  wood  beneath  lower  sash  of 
window. 


44.  Stete  wliat  Florence  Nightingale  says  about  inhaling  night  air? 


176  RESPIRATION. 

understand,  in  towns,  shutting  the  windows  during  the  day  than 
during  the  night."     (Read  Note  9.) 

.  A._45.  Animal  Heat. — Intimately  connected  with  respiration  is  the 
S^V  production  of  animal  heat,  or  the  power  of  maintaining  the  tempera- 
ture of  the  body  above  that  of  the  medium  in  which  the  creature 
moves ;  thus,  the  bird  is  warmer  than  the  air,  and  the  fish  than 
the  water.  This  elevation  of  temperature  is  the  result  of  the  va- 
rious chemical  changes  which  are  constantly  taking  place  in  the 
system.  Although  common  to  all  animals,  in  a  greater  or  less  de- 
gree, heat  is  not  peculiar  to  them,  since  plants  also  generate  it, 
especially  at  the  time  of  sprouting  and  flowering.  If  a  thermometer 
be  placed  in  a  cluster  of  geranium  flowers,  it  will  indicate  a  tem- 
perature several  degrees  above  that  of  the  surrounding  air. 

46.  Among  animals  great  differences  are  noticed  in  this  respect, 
but  the  degree  of  heat  produced  is  always  proportional  to  the  activ- 
ity of  respiration  and  the  amount  of  oxygen  consumed.  Accord- 
ingly, the  birds,  whose  habits  are  extremely  active,  and  whose 
breathing  capacity  is  the  greatest,  have  uniformly  the  highest  tem- 
perature. Sluggish  animals,  on  the  contrary,  as  frogs,  lizards,  and 
snakes,  have  little  need  for  oxygen,  and  have  incompletely  developed 
lungs ;  these  animals  are  cold  to  the  touch — that  is,  they  have  rela- 
tively a  lower  temperature  than  man,  and  their  positive  temperature 

9.  Pure  Air  in  our  Homes  during  Cold  Weather.— "Fresh  aii 
is  the  great  natural  disinfectant,  antiseptic,  and  purifier,  and  not  to  be  com- 
pared for  a  moment  with  any  of  artificial  contrivance.  There  is  plenty  of  it 
in  the  world ;  yet,  disguise  the  fact  as  we  may,  there  is  no  getting  over  the. 
unwelcome  truth,  that  to  provide  it  in  abundance  in  our  climate  is  expensive, 
since  during  seven  months  in  the  year  it  must  be  artificially  warmed,  in  order 
that  our  homes  may  be  comfortable.  To  take  in  air  at  the  average  winter 
temperature  of  28°,  raise  it  to  68°,  and  discharge  it  again  from  our  houses  even 
once  in  an  hour,  is  a  process  which  cannot  be  accomplished  without  paying 
roundly  ;  yet  on  no  other  condition  can  we  reasonably  expect  health  and  long 
life.  The  best  way  is  to  freely  admit  that  it  is  expensive,  but  worth  the  money 
it  costs.  If  Benjamin  Franklin  thought  that  'a  penny  saved  is  a  penny 
earned,'  he  is  equally  sure  that  *  health  is  wealth.'" — George  Derby  on  the 
Prevention  of  Disease. 

45.  Warmth  of  the  bird  as  compared  with  that  of  the  air?    Of  the  fish  and  the  water? 
Heat  in  animals  and  plants  ?    How  illustrated  with  the  thermometer  ? 

46.  Amount  of  heat  in  animals,  how  apportioned  f    As  regards  the  birds     Ffrogs,  and 
*ther  sluggish  animals  ?    Arrangement  made  by  zoologists  ? 


RESPIRATION.  177 

is  but  little  above  that  of  the  external  air.  Accordingly,  zoologists 
have  so  arranged  the  animal  kingdom  that  warm-blooded  animals, 
including  man,  the  birds,  and  the  quadrupeds,  are  classified  to- 
gether; while  the  cold-blooded  animals,  such  as  the  fish,  tortoise, 
frog,  and  all  that  have  no  vertebral  column,  are  classed  by  them- 
selves. 

47.  The  temperature  of  the  human  body  is  about  100°  Fahren- 
heit, and  remains  about  the  same  through  winter  and  summer — in 
the  tropics  as  well  as  in  the  frozen  regions  of  the  north.     It  may 
change  temporarily  within  the  range  of  about  twelve  degrees ;  but 
any  considerable,  or  long-continued  elevation  or  diminution  of  the 
bodily  heat  is  certain  to  result  disastrously. 

48.  Man  is  able  to  adapt  himself  to  all  extremes  of  climate; 
and,  in  fact,  by  means  of  clothing,  shelter,  and  food,  is  able  to 
create  for  himself  an  artificial  climate  wherever  he  chooses  to  reside. 
The  power  to  resist  cold  consists  chiefly  in  preventing  the  heat 
which  is  generated  by  the  vital  processes  of  the  body  from  being 
lost  by  radiation.     Warm  clothing,  such  as  we  wear  in  winter,  has, 
in  reality,  the  same  temperature  as  that  which  is  worn  in  summer ; 
but,  by  reason  of  being  thick  and  porous,  it  is  a  bad  conductor  of 
heat,  and  thus  prevents  the  escape  of  that  produced  by  the  body. 
If  woollen  fabrics  were  intrinsically  warm,  no  one  would  wrap  a 
piece  of  flannel,  or  blanket,  around  a  block  of  ice  to  prevent  its 
melting  in  summer. 

49.  The  faculty  of  generating  heat  explains  how  it  is  that  we 
are  enabled  to  resist  the  effects  of  cold ;  but  how  does  the  body 
withstand  a  temperature  higher  than  its  own]     Men  have  been 
known  to  remain  several  minutes  in  ah  atmosphere  heated  above 
the  boiling-point  of  water,  and  yet  the  temperature  of  their  own 
bodies  was  not  greatly  increased.     Those  who  labor  in  foundries 
and  glass-works  are  habitually  subjected  to  very  high  degrees  of 
temperature,  but  they  do  not  suffer  in  health  more  than  those  en- 
gaged in  many  other  occupations. 

50.  The  regulation  of  the  temperature  of  the  body  is  effected  by 

47.  State  what  is  said  respecting  the  temperature  of  the  human  body. 

48.  Ability  of  man  to  adapt  himself  to  different  climates?    In  what  does  the  power  to 
Tesist  cold  consist  ?    What  is  said  about  warm  clothing  ? 

49.  Men  in  an  atmosphere  above  the  boiling-point  ?    In  foundries  and  glass-works  ? 
60.  The  regulation  of  the  temperature  of  the  body.    Give  the  explanation 


178  '  RESPIRATION. 

means  of  perspiration,  and  by  its  evaporation.  So  long  as  the  skin 
acts  freely,  and  the  air  freely  absorhs  the  moisture,  the  heat  of  the 
body  does  not  increase,  for  whenever  evaporation  takes  place,  it  is 
attended  with  the  abstraction  of  heat — that  is,  the  part  becomes 
relatively  colder.  This  may  be  tested  by  moistening  some  part  of  the 
surface  with  cologne,  ether,  or  other  volatile  liquid,  and  then  caus- 
ing it  to  evaporate  rapidly  by  fanning.  The  principle  that  evapo- 
ration produces  cold  has  been  ingeniously  and  practically  employed, 
in  the  manufacture  of  ice  by  means  of  freezing  machines. 

51.  Spontaneous  Combustion — Alcohol  the  Indirect  Cause. — 
Is  it  possible  that  the  temperature  of  the  living  body  can  be  so  in- 
creased that  its  tissues  will  burn  spontaneously  ?      From  time  to 
time  cases  have  been  reported  in  which,  by  some  mysterious  means, 
considerable  portions  of  the  human  body  have  been  consumed,  ap- 
parently by  fire — the  victim  being  found  dead,  or  incapable  of  explain- 
ing the  occurrence.     Hence,  the  theory  has  been  current  that,  under 
certain  conditions,  the  tissues  of  the  body  might  become  self-ignited; 
and  the  fact  that  this  so-called  spontaneous  combustion  has  ordinarily 
taken  place  in  those  who  had  been  addicted  to  the  use  of  alcoholic 
drinks,  has  given  a  color  of  probability  to  the  opinion.     It  has  been 
supposed  that  the  flesh  of  these  unfortunate  persons,  becoming  sat- 
urated with  alcohol  thus  taken  into  the  system,  took  fire  upon  being 
exposed  to  a  flame,  as  of  a  lighted  candle,  or,  indeed,  without  any 
external  cause.     But,  whether  this  be  possible  or  not,  one  thing  is 
certain — this  strange  kind  of  combustion  has  never  been  actually 
witnessed  by  any  one  competent  to  give  a  satisfactory  account  of  it. 

52.  The  results  that  have  been  observed  may  be  satisfactorily 
explained  by  the  accidental  ignition  of  the  clothes,  or  other  articles 
near  the  body,  and    by  the  supposition  that    the  individual  was 
at   the   time   too    much    stupefied   by   intoxication,  to  notice  the 
source  of  danger  and  provide  for  his  safety.     The  highest  tempera- 
ture that  has  been  observed  in  the  body — about  112°  Fahrenheit — is 
too  low  to  ignite  the  vapor  of  alcohol ;  much  less  will  it  cause  the 
burning  of  animal  tissues.     It  is  undoubtedly  true  that  when  the 
tissues  are  filled  with  alcohol,  combustion  will  more  easily  take 

51.  State  what  is  said  of  spontaneous  combustion. 

52.  How  is  the  theory  refuted  ? 


RESPIRATION.  179 

place  than  when  the  body  is  in  a  normal  state ;  but,  under  any  con- 
dition, the  combustion  of  the  body  requires  a  higher  degree  of  heat 
than  can  be  generated  by  the  body  itself,  or  the  mere  proximity  of 
a  lighted  candle,  or  any  cause,  of  similar  character. 

53.  The    Effect   of  Alcohol    upon    Respiration. — Whenever 
wine,  or  any  other  form  of  alcoholic  drink,   is   taken   into   the 
stomach,  it  is  quite  rapidly  absorbed  into  the  blood-current,  and  in 
a  few  minutes  it  imparts  to  the  breath  a  peculiar,  offensive  odor. 
This  is  due  to  the  vapor  of  alcohol  that,  little  by  little,  is  expelled 
from  the  body,  along  with  the  carbonic  acid  gas  exhaled  through 
the  lungs.     If  the  quantity  of  drink  taken  has  been  considerable, 
this  disagreeable  odor  may  continue  a  day  or  more. 

This  condition  is  evidence  that  an  unnatural  labor  has  been 
thrown  upon  the  lungs ;  namely,  it  is  an  effort  on  the  part  of  the 
general  system  to  get  rid  of  a  poison  that  is  hurtful  to  every  organ 
by  which  it  is  retained.  While  this  exhalation  of  alcoholic  vapor 
continues,  the  respiratory  act  is  impaired,  for  not  only  can  less  car- 
bonic acid  gas  be  thrown  off,  but  there  is  also  a  diminished  inhala- 
tion of  oxygen. 

54.  Respiratory   Diseases    among    the    Intemperate.  —  The 
structure  of  the  respiratory  organs  is  such  that  they  are  relatively 
tolerant  of  the  presence  of  alcohol  in  the  body. 

Wheezy  breathing  and  hoarseness  of  voice  are  noticeable  among 
inebriates ;  but  this  class  does  not  suffer  greatly  from  severe  attacks 
of  lung  diseases  that  can  be  said  to  be  directly  due  to  the  liquor  they 
drink.  Indirectly,  however,  they  suffer  greatly,  as  a  class,  from 
those  diseases,  because  they  incur  exposures  of  every  imaginable 
variety,  while  under  the  intoxicant  influence  of  this  powerful  drug, 
which  can,  according  as  it  is  taken  in  less  or  greater  quantity,  de- 
prive a  person  of  his  sober  self-management  or  bring  him  down  to 
utter  loss  of  consciousness.  It  is  in  this  way  that  the  users  of  alco- 
hol fall  a  prey,  especially  in  the  winter  season,  to  attacks  of  pneu- 
monia, or  lung  fever,  and  other  serious  disease  of  the  respiratory 
organs. 

53.  Does  alcohol  appear  in  the  breath  ?    Does  it  interfere  with  respiration  ? 
64.  What  respiratory  diseases  among  the  intemperate  f 


180 


QUESTIONS    FOR  TOPICAL  REVIEW. 


PAGE 

1.  What  Is  the  object  of  respiration  ?  ......................................  „  ......  t.  154 

2.  What  are  the  special  organs  of  respiration  ?  ......................................  154 

3.  In  what  organs  does  a  change  in  the  blood  take  place?  ......................  .  ----  154 

4.  What  is  the  nature  of  the  change?  ........................  ........................  154 

5.  Where  are  the  lungs  situated,  and  what  is  the  character  of  the  substance  of  which 

they  are  composed?  ...........................  ....  ...........................  154 

6.  Describe  the  facilities  provided  for  the  lung  movements  .......................  154,  155 

7.  Describe  the  trachea,  or  windpipe  ............................................  155-158 

8.  Describe  the  bronchial  tubes,  and  their  uses  .....................  .............  155,156 

9.  What  can  you  state  in  relation  to  the  epiglottis  ?  ............................  156,157 

10.  What  are  the  cilia  and  what  use  do  they  probably  serve?.  ...  ............  .  .........  157 

11.  How  may  the  lungs  be  affected  by  not  being  properly  protected  ?  ...................  158 

12.  Describe  the  movements  necessary  to  the  act  of  perfect  respiration  .................  159 

13.  What  is  the  diaphragm,  .and  what  is  its  office  ?  ....................................  159 

14.  How  may  the  organs  of  respiration  be  so  improved  as  to  increase  their  capacity  and 

power?  .......................................................................  159 

15.  What  is  stated  in  relation  to  the  frequency  of  respiration  ?  ....................  159,  160 

16.  To  what  extent  may  the  act  of  respiration  be  subjected  to  our  wills  ?  ...............  160 

17.  What  may  be  said  to  be  the  capacity  of  the  lungs?  ................................  160 

18.  How  long  does  it  take  every  particle  of  air  in  the  lungs  to  be  expelled  and  new  air  to 

take  its  place?  ..........................................................  160,161 

19.  What  would  be  the  consequences,  if  the  entire  capacity  of  the  lungs  were  constantly 
^      used?  ........................................................................  161 

20.  What  would  be  the  consequences  to  a  fish  put  into  water  from  which  the  air  had 

been  completely  exhausted  ?    Why?.....  ......................................  161 

21.  What  is  the  air,  and  what  are  its  parts  ?.X^..>  ........  -  ..............  -.  .......  162,163 

22.  What  is  the  character  of  the  air  that  has  been  just  breathed  ?  ......  ................  162 

23.  Why  is  it  that  such  air  is  not  fit  for  respiration?  .............................  163,164 

24.  What  are  the  effects,  as  recorded  in  notable  cases  of  confinement  in  places  the  air  of 

which  has  been  breathed  "over  and  over?"....  .................................  163 

25.  What  can  you  state  of  changes  in  the  blood  from  respiration  ?  ......................  164 

26.  What  of  the  air  as  an  article  of  food?  .............................................  164 

27.  What  on  the  subject  of  interchange  of  gases  in  the  lungs  ?  .....................  164,  165 

28.  Explain  the  difference  between  arterial  and  venous  blood  ..........................  165 

29.  Explain,  if  you  can,  the  cause  of  the  difference..  .....     ...........................  165 

80.  State  what  you  can  in  relation  to  blue  blood  .  ....................................  165 

81.  In  relation  to  the  amount  of  labor  exerted  in  respiration  ...........................  166 

82.  In  relation  to  the  deleterious  properties  of  different  gases  ......................  166,  167 

83.  In  relation  to  the  dust  that  floats  in  the  air  ......................................  168 

34  What  are  the  properties  of  carbonic  acid  gas?  ................  .  .,  ..............  168,169 

85.  In  what  places  is  carbonic  acid  gas  commonly  found  ?  ..............................  169 

86.  Describe  the  effects  of  carbonic  acid  gas  .................................     .  .....  169 

87.  What  are  the  general  effects  of  breathing  any  impure  atmosphere  ?  ............  169-172 

88.  What  are  Nature's  provisions  for  purifying  the  air  ?  ...........................  172,  173 

89.  What  hints  and  directions  are  given  on  the  subject  of  ventilation  ?  .............  174,  175 

40.  How  does  the  temperature  of  the  body  compare  with  the  medium  in  which  it  lives?  176 

41.  How  is  temperature  of  the  body  regulated  and  sustained  ?.....  ............  ..  .  .  177,  ]  78 

ft.  State  what  you  can  on  the  subject  of  spontaneous  combustion  ......  ......  ........  172 


IX. 

THE  NERVOUS  SYSTEM. 

Animal  and  Vegetative  Functions  Sensation,  Motion,  and  Volition — The 
Structure  of  the  Nervous  System — The  White  and  Gray  Substances — Th^ 
Brain  —  Its  Convolutions — The  Cerebellum — The  Spinal  Cord  and  its 
System  of  Nerves — The  Anterior  and  Posterior  Roots — The  Sympathetic 
System  of  Nerves — The  Properties  of  Nervous  Tissue — Excitability  of  Nerv- 
ous Tissues — The  Functions  of  the  Spinal  Nerves  and  Cord — The  Direction 
of  the  Fibres  of  the  Cord — Reflex  Activity,  and  its  Uses — The  Functions  of 
the  Medulla  Oblongata  and  the  Cranial  Ganglia — The  Reflex  Action  of  the 
Brain — Effects  of  Alcohol,  Tobacco,  Snuff,  Narcotics,  Opium,  Chloral, 
Hasheesh,  Chloroform. 

1.  Animal  Functions. — The  vital  processes  which  we  have  been 
considering  in  the  three  previous  chapters — of  digestion,  circulation, 
and  respiration — belong  to  the  class  of  functions  known  as  vegeta- 
tive functions.     That  is,  they  are  common  to  vegetables  as  well  as 
animals ;  for  the  plant,  like  the  animal,  can  originate  nothing,  not 
even  the  smallest  particle  of  matter ;  and  yet  it  grows,  blossoms, 
and  bears  fruit,  by  reason  of  obtaining  and  digesting  the  nutriment 
which  the  air  and  soil  provide.     The  plant  has  its  circulatory  fluid 
and  channels,  by  which  the  nutriment  is  distributed  to  all  its  parts. 
It  has,  also,  a  curious  apparatus  in  its  foliage,  by  which  it  abstracts 
from  the  air  those  gaseous  elements  so  necessary  to  its  support ;  and 
thus  it  accomplishes  vegetable  respiration.     These  vegetative  func- 
tions have  their  beginning  and  end  within  the  organism  of  the 
plant ;  and  their  object  is  the  preservation  of  the  plant  itself,  as 
well  as  of  the  entire  species. 

2.  The  animal,  in  addition  to  these  vegetative  functions,  has  an- 
other set  of  powers,  by  the  use  of  which  he  becomes  conscious  of  a 
world  external  to  himself,  and  brings  himself  into  active  relations 

1.  What  processes  are  known  as  the  vegetative  functions  ?    Why  so  called  ?    What  prop- 
erties and  functions  does  the  plant  possess  ?    Their  object  ? 

2.  What  second  set  of  powers  has  the  animal  ?    What  functions  are  mentioned  ?    The  a& 
vantage  they  give? 


182  THE   NERVOUS   SYSTEM. 

with  it.  By  means  of  the  vegetative  processes,  his  life  and  species 
are  maintained ;  while,  by  means  of  certain  animal  functions,  he 
feels,  acts,  and  thinks.  These  functions,  among  which  are  sensa- 
"^v  tion,  motion,  and  volition,  not  only  distinguish  the  animal  from  the 
plant,  but,  in  proportion  to  their  development,  elevate  one  creature 
above  another ;  and  it  is  by  virtue  of  his  pre-eminent  endowment, 
in  these  respects,  that  man  holds  his  position  at  the  head  of  the 
animal  creation. 

3.  Among  animals  whose  structure  is  very  simple — the  hydra,  or 
fresh-water   polyp,  being  an  example — no  special  organs   are  em- 
powered to  perform  separate  functions,  but  every  part  is  endowed 
alike ;  so  that,  if  the  animal  be  cut  into  pieces,  each  portion  has  all 
the  properties  of  the  entire  original ;  and,  if  the  circumstances  be 
favorable,  each  of  the  pieces  will  soon  become  a  complete  hydra. 
As  we  approach  man,  in  the  scale  of  beings,  we   find   that  the 
organs  multiply,  and  the  functions  become  more  complete.     The 
function  of  motion,  the  instruments  of  which — the  muscles  and 
bones — have  been  considered  in  former  chapters,  and  all  the  other 
animal  functions  of  man,  depend  upon  the  set  of  organs  known  as 
the  nervous  system. 

4.  The  Nervous  System. — The  intimate  structure  of  this  sys~ 
tern  differs  from  any  tissue  which  we  have  before  examined.     It  is 
composed  of  a  soft,  pulpy  substance,  which  early  in  life  is  almost 
fluid,  but  which  gradually  hardens  with  the  growth  of  the  body. 
When  examined  under  the  microscope,  it  is  found  to  be  composed 
of  two  distinct  elements :  (1)  the  white  substance,  composing  the 
larger  proportion  of  the  nervous  organs  of  the  body,  which  is  formed 
of  delicate  cylindrical  filaments,  about  ^-gVg-  of  an  inch  in  diameter, 
termed  the  nerve-fibres ;  and  (2)  the  gray  substance,  composed  of 
grayish-red,  or  ashen-colored  cells,  of  various  sizes,  generally  possess- 
ing one  or  more  off-shoots,  which  are  continuous  with  the  nerve- 
fibres  just  mentioned. 

5.  The  gray,  cellular  substance  constitutes  the  larger  portion  of 

8.  Animals  whose  structure  is  simple?    As  we  approach  man?    Dependence  of  the 
animal  functions  of  man? 

4.  The  nervous  tissues,  of  what  composed  ?    When  examined  by  the  aid  of  the  microscope  ? 
The  white  substance  ?    The  gray  substance  ? 

5.  Nervous  centres  and  ganglia?     Nerves?     What  do  they  serve?     Cerebro-spinal 
system? 


THE    NERVOUS   SYSTEM.  183 

those  important  masses  which  bear  the  name  of  nervous  centres  and 
ganglia  (from  ganglion,  a  knot),  in  which  all  the  nerve-fibres  unite. 
These  white  nerve-fibres  are  found  combined  together  in  long  and 
dense  cords,  called  nerves  (from  neuron,  a  cord),  which  serve  to 
connect  the  nervous  centres  with  each  other,  and  to  place  them  in 
communication  with  all  the  other  parts  of  the  body  which  have 
sensibility  or  power  of  motion.  That  part  of  the  nervous  system 
which  is  concerned  in  the  animal  functions  comprises  the  brain,  the 
spinal  cord,  and  the  nerves  which  are  derived  therefrom ;  these  are, 
together,  called  the  cerebro-spinal  system  (Fig.  48) ;  while  that 
other  set  of  organs,  which  presides  over  and  regulates  the  vege- 
tative functions^  is  called  the  sympathetic  system  of  nerves. 

6.  The  Brain. — The  brain  is  the  great  volume  of  nervous  tissue 
that  is  lodged  within  the  skull.     It  is  the  largest  and  most  complex 
of  the  nervous  centres ;  its  weight,  in  the  adult,  being  about  fifty 
ounces,  or  one-fortieth  of  that  of  the  whole  body.    The  shape  of  the 
brain  is  oval,  or  egg-shaped,  with  one  extremity  larger  than  the 
other,  which  is  placed  posteriorly  in  the  skull,  to  the  concavity  of 
which  it  very  closely  conforms.     The  brain  consists  chiefly  of  two 
parts ;  the  cerebmm,  or  brain  proper,  and  the   cerebellum,  or  "  little 
brain."     In  addition  to  these,  there  are  several  smaller  organs  at  the 
base,  among  which  is  the  commencement  or  expansion  of  the  spinal 
cord,  termed  the  medulla  oblongata,  or  oblong  marrow. 

7.  The  tissue  of  the  brain  is  soft  and  easily  altered  in  shape  by 
pressure ;  it  therefore  requires  to  be  placed  in  a  well-protected  position, 
such  as  is  afforded  by  the  skull,  or  cranium,  which  is  strong  with- 
out being  cumbrous.     In  the  course  of  an  ordinary  lifetime,  this  bony 
box  sustains  many  blows  with  little  inconvenience  ;  while,  if  they 
fell  directly  upon  the  brain,  they  would  at  once,  and  completely, 
disorganize  that  structure.     Within  the  skull,  the  brain  is  enveloped 
by  certain  membranes,  which  at  once  protect  it  from  friction  and 
furnish  it  with  a  supply  of  nutrient  vessels ;  they  are  called  the 
arachnoid,  or  "  spider's  web,"  the  dura  mater,  and  the  pia  mater,  or 
the  "tough"  and  "delicate  coverings."     The  supply  of  blood  sent 

6.  Location  of  the  brain?    Its  weight?    Its  shape?    Of  what  it  consists?    What  organs 
at  the  base? 

7.  The  tissue  of  the  brain?    What,  therefore,  is  required?    Blows  on  the  head?    Mem- 
branes of  the  brain  ?    Blood  sent  to  the  brain  ? 


184 


THE   NERVOUS   SYSTEM. 


FIG.  48.— THS  CEREBRO-SPINAL  SYSTEM. 


THE   NERVOUS    SYSTEM. 


185 


to  the  brain  is  very  liberal,  amounting  to  one-fifth  of  all  that  the 
entire  body  possesses.  The  brain  of  man  is  heavier  than  that  of 
any  other  animal,  except  the  elephant  and  whale. 

8.  The  Cerebrum. — The  brain  proper,  or  cerebrum,  is  the 
largest  of  the  intracranial  organs,  and  occupies  the  entire  upper  and 
front  portion  of  the  skull.  It  is  almost  completely  bisected  by  a 
fissure,  or  cleft,  running  through  it  lengthwise,  into  two  equal  parts 
called  hemispheres.  The  exterior  of  these  hemispheres  is  gray  in 
color,  consisting  chiefly  of  nerve-cells,  arranged  so  as  to  form  a  layer 
of  gray  matter  one-fifth  of  an  inch  in  thickness,  and  is  abundantly 
supplied  with  blood-vessels.  The  interior  of  the  brain,  however,  is 
composed  almost  wholly  of  white  substance,  or  nerve-fibres. 
_x^--8rr*The  surface  of  the 
cerebrum  is  divided  by  a 
considerable  number  of 
winding  and  irregular  fur- 
rows, about  an  inch  deep, 
into  "  convolutions,"  as 
shown  in  Fig.  49.  Into 
these  furrows  the  gray 
matter  of  the  surface  is 
extended,  and,  in  this 
manner,  its  quantity  is 
vastly  increased.  The  ex- 
tent of  the  entire  surface 
of  the  brain,  with  the 
convolutions  unfolded,  is 
computed  to  be  equal  to 
four  square  feet ;  and  yet 
it  is  easily  enclosed  within 
the  narrow  limits  of  the 
skull.  When  it  is  stated 
that  the  gray  matter  is 
the  true  source  of  nervous  power,  it  becomes  evident  that  this 

8.  Size  of  the  brain  proper?    How  divided?    The  exterior  of  the  hemispheres?    The  in- 
terior? 

9.  The  surface  of  the  cerebrum,  how  marked?    The  gray  matter  of  the  surface?    Exteat 
of  the  entire  brain  surface  ?    Source  of  nervous  power  ?    What  further  ? 


FIG.  49. — UPPER  SURFACE  OF  THE  CEREBRUM. 

A,  Longitudinal  Fissure. 

B,  The  Hemispheres. 


186  THE   NERVOUS   SYSTEM. 

arrangement  has  an  important  bearing  on  the  mental  capacity  of 
the  individual.  And  it  is  noticed  that  in  children,  before  the  mind 
is  brought  into  vigorous  use,  these  markings  or  furrows  on  the  sur- 
face are  comparatively  shallow  and  indistinct ;  the  same  fact  is  true 
of  the  brain  in  the  less  civilized  races  of  mankind  and  in  the  lower 
animals.  It  is  also  noticeable  that  among  animals,  those  are  the 
most  capable  of  being  educated  which  have  the  best  development  oi 
the  cerebrum.  (Read  ATote  i.) 


A---, 


FIG.  50.— VERTICAL  SECTION  OF  THE  BRAIN. 

A,  Left  Hemisphere  of  Cerebrum.  D,  The  Pons  Varolii. 

B,  Corpus  Callosum.  E,  Upper  extremity  of  the  Spinal  Cord. 

C,  Optic  Thalamus.  F,  The  Arbor  Vitse. 

1.  The  Brain. — "Our  brains  are  seventy-year  clocks.  The  Angel  of  Life 
winds  them  up  once  for  all,  then  closes  the  case,  and  gives  the  1cey  to  the 
Angel  of  the  Resurrection.  Tic-tac  !  tic-tac  !  go  the  wheels  of  thought ;  out 
will  cannot  stop  them  ;  they  cannot  stop  themselves  ;  sleep  cannot  stop  them  ; 
madness  only  makes  them  go  faster  ;  death  alone  can  break  into  the  case,  and, 
seizing  the  ever-swinging  pendulum,  which  we  call  the  heart,  silence  at  last 
the  clicking  of  the  terrible  escapement  we  have  carried  so  long  beneath  our 
wrinkled  foreheads.  *  Now,  when  a  gentleman's  brain  is  ill-regulated 

or  empty,  it  is,  to  a  great  extent,  his  own  fault,  and  so  it  is  simple  retribution 
that,  while  he  lies  slothfully  or  aimlessly  dreaming,  the  fatal  habit  settles  on 
him  like  a  vampire  and  sucks  his  blood,  fanning  him  all  the  while  with  its  hot 
wings  into  deeper  slumber  or  idler  dreams. " — Holmes'  The  Autocrat  of  the 
Breakfast- Table. 


THE   NEKVOUS   SYSTEM.  187 

10.  The  Cerebellum. — The  "  little  brain"  is  placed  beneath  the 
posterior  part  of  the  cerebrum,  and,  like  the  latter,  is  divided  into 
hemispheres.  Like  it,  also,  the  surface  of  the  cerebellum  is  com- 
posed of  gray  matter,  and  its  interior  is  chiefly  white  matter.  It 
has,  however,  no  convolutions,  but  is  subdivided  by  many  parallel 
ridges,  which,  sending  down  gray  matter  deeply  into  the  white, 
central  portion,  give  the  latter  a  somewhat  branched  appearance. 
This  peculiai  appearance  has  been  called  the  arbor  vtfce,  or  the 
"tree  of  life,"  from  the  fact  that  when  a  section  of  the  organ  is 
made,  it  bears  some  resemblance  to  the  trunk  and  branches  of  a 
tree  (Fig.  50,  F).  In  size,  this  cerebellum,  or  "  little  brain,"  is  less 
than  one-eighth  of  the  cerebrum. 


FIG.  51.— LOWER  SURFACE  OF  THE  BRAIN. 
The  numbers  refer  to  the  pairs  of  nerves. 

II.  From  the  under  surface  of  the  cerebrum,  and  from  the  front 
margin  of  the  cerebellum,  fibres  collect  together  to  form  the  medulla 
oUongata  (Fig.  51,  Ma),  which,  on  issuing  from  the  skull,  enters 
the  spinal  column,  and  then  becomes  known  as  the  spinal  cord. 

10.  Location  of  the  "little  brain?"    How  divided?    Its  surface  and  interior?    Its  sub- 
divisions ?    Its  size  ? 

11.  Medulla  oblougata?    Crania.1  nerves?    Their  shape  and  position  ? 


188 


THE   NERVOUS   SYSTEM. 


From  the  base  of  the  brain,  and  from  the  sides  of  the  medulla 
originate,  also,  the  cranial  nerves,  of  which  there  are  twelve  pairs. 

These  nerves  are  round  cords  of  glisten- 
ing  white  appearance,  and,  like  the 
arteries,  generally  lie  remote  from  the 
surface  of  the  body,  and  are  well  pro- 
tected from  injury. 

12.  The  Spinal  Cord.—  The  spinal 
cord,  or  "  marrow,"  is  a  cylindrical  mass 
of  soft  nervous  tissue,  which  occupies  a 
chamber,  or  tunnel,  fashioned  for  it  in 
the  spinal  column  (Figs.  52  and  53). 
It  is  composed  of  the  same  substances 
as  the  brain;  but  the  arrangement  is  ex- 
actly reversed  —  the  white  matter  encom- 
passing or  surrounding  the  gray  matter, 
instead    of    being   encompassed  by  it. 
The  amount  of  the  white  substance  is 
also  greatly  in  excess  of  the  other  mate- 
rial.    A  vertical  fissure  partly  separates 

.the  cord  into  two  lateral  halves,  and 
each  half  is  composed  of  two  separate 
bundles  of  fibres,  which  are  named  the 
anterior  and  posterior  columns. 

13.  These  columns  have  entirely  dif- 
ferent uses,  and  each  of  them  unites  with 
a  different  portion  of  the  nerves  which 
have   their  origin   in   the  spinal  cord. 
The    importance  of    this   part  of  the 
nervous  system  is  apparent  from  the 
extreme  care  taken  to  protect  it  from 
external  injury.    For,  while  a  very  slight 
disturbance  of  its  structure  suffices  to 
disarm  it  of  its  power,  yet  so  staunch 

ty 


52. 


A,  CEJEBRUM^CEREBELLrM, 


12  The  spinal  cord  *    Of  what  composed  ?    How  divided  ?    Each  half? 
13.  Uses  of  these  columns?    Importance  of  this  part  of  the  nervous  system  ?    How  pn> 
tected? 


THE   NERVOUS   SYSTEM.  189 

severe  injuries  is  it  put  in  peril  The  three  membranes  that  cover 
the  brain  are  continued  downward,  so  as  to  envelope  and  still  fur- 
ther shield  this  delicate  organism. 

14.  The  Spinal  Nerves. — The  spinal  nerves,  thirty-one  pairs  in 
number,  spring  from  each  side  of  the  cord  by  two  roots,  an  anterior 
and  a  posterior  root,  which  have  the  same  functions  as  the  columns 
bearing  similar  names.  The  posterior  root  is  distinguished  by  pos- 
sessing a  ganglion  of  gray  matter,  and  by  a  somewhat  larger  size 


Pro.  53.— SECTION  OF  SPINAL  COED,  WITH  ROOTS  OF  SPINAL  NERVES.    FRONT  VIEW. 

The  successive  points  of  departure,  or  the  off-shooting  of  these 
nerves,  occur  at  short  and  nearly  regular  intervals  along  the  course 
of  the  spinal  cord.  Soon  after  leaving  these  points,  the  anterior 
and  posterior  roots  unite  to  form  the  trunk  of  a  nerve,  which  u 
distributed,  by  means  of  branches,  to  the  various  organs  of  that 
part  of  the  body  which  this  nerve  is  designed  to  serve.  The  spinal 
nerves  supply  chiefly  the  muscles  of  the  trunk  and  limbs  and  the 
external  surface  of  the  body. 

15,  The  tissue  composing  the  nerves  is  entirely  of  the  white 
variety,  or,  in  other  words,  the  nerve-fibres;  the  same  as  we  have 
observed  forming  a  part  of  the  brain.  But  the  nerves,  instead  of 
being  soft  and  pulpy,  as  in  the  case  of  the  brain,  are  dense  in 
structure,  being  hardened  and  strengthened  by  means  of  a  fibrous 
tissue  which  surrounds  each  of  these  delicate  fibres,  and  binds  them 
together  in  glistening,  silvery  bundles.  Delicate  and  minutely  fine 
as  are  these  nerve-fibres,  it  is  probable  that  each  of  them  pursues 
an  unbroken,  isolated  course,  from  its  origin,  in  the  brain  or  else- 

14.  The  spinal  nerves?    The  posterior  root?    The  nerves,  how  arranged?    Their  office? 

15.  The  nerve  tissue  ?    Its  character  ?    Course  of  each  nerve  fibre  ? 


190  THE   NERVOUS   SYSTEM. 

where,  to  that  particular  point  which  it  is  intended  to  serve.  For. 
although  their  extremities  are  often  only  a  hair's  breadth  distant 
from  each  other,  the  impression  which  any  one  of  them  communi- 
cates is  perfectly  distinct,  and  is  referred  to  the  exact  point  whence 
it  came. 

16.  This  may  be  illustrated  in  a  simple  manner,  thus:  if  two 
fingers  be  pressed  closely  together,  and  the  point  of  a  pin  be  carried 
lightly  across  from  one  to  the  other,  the  eyes  may  be  closed,  and 
yet  we  can  easily  note  the  precise  instant  when  the  pin  passes  from 
one  finger  to  the  other.     If  the  nerve-fibres  were  less  independent, 
and  if  it  were  necessary  that  they  should  blend  with  and  support 
each  other,  all  accuracy  of  perception  would  be  lost,  and  all  infor- 
mation thus  afforded  would  be  pointless  and   confused.      These 
silvery  threads  must,  therefore,  be  spun  out  with  an  infinite  degree 
of  nicety.    Imagine,  for  instance,  the  fibre  which  connects  the  brain 
with  some  point  on  the  foot — its  length  cannot  be  less  than  one 
hundred  thousand  times  greater  than  its  diameter,  and  yet  it  per- 
forms its  work  with  as  much  precision  as  fibres  that  are  compara- 
tively much  stronger,  and  less  exposed.     (Read  Note  2.) 

17.  The  Sympathetic  System. — The   sympathetic  system  of 
nerves  remains  to  be  described.     It  consists  of  a  double  chain 

2.  How  Bodily  Sensations  are  Located.— "A  nervous  fibre  which 
ends  in  the  skin  forms,  as  far  as  its  union  with  the  brain  or  cord  is  concerned, 
one  long,  fine,  unbroken  thread.  The  fibres,  thus  ending  in  the  skin,  very 
soon  join  to  form  small  branches,  and  finally  in  thick  nerve  trunks,  but  in  no 
case  do  two  nerve  fibres  coalesce  so  as  to  lose  their  identity.  Every  part  of 
the  skin  has  its  own  separate  connections  with  the  centre  of  the  nervous 
system,  which  unite  there  just  as  telegraph  wires  unite  at  a  terminus.  The 
brain  is  the  terminus  of  these  lines  of  nerves,  and,  as  it  were,  receives  and  ex- 
plains the  messages  sent  to  it.  It  distinguishes  very  clearly  by  what  particular 
fibre  such  a  message  has  come,  and  just  as  the  clerk  in  a  telegraph  office, 
where  a  great  many  wires  meet  from  all  sides,  knows  by  experience  from  what 
direction  each  wire  brings  its  message,  so  the  brain  also  knows  by  experience 
what  part  of  the  skin  is  involved  when  a  sensation  reaches  it  along  a  certain 
nerve  fibre,  It  is  probable  that  the  brain,  by  its  imaginative  faculty, 
has  formed  a  complete- picture  of  the  surface  of  the  body — a  kind  of  chart 

16.  How  may  we  illustrate  the  fact  ?    The  fibre  connecting  the  brain  with  a  poiut  in  the 
foot? 

17.  The  sympathetic  system  of  nerves  ?    Of  what  does  it  consist  ? 


THE    NERVOUS    SYSTEM.  191 

of  ganglia,  situated  on  each  side  of  the  spinal  column,  and  extend- 
ing through  the  cavities  of  the  trunk,  and  along  the  neck  into  the 
head.  These  ganglia  are  made  up  for  the  most  part  of  small  col- 
lections of  gray  nerve-cells,  and  are  the  nerve-centres  of  this 
system,/  From  these,  numerous  small  nerves  are  derived,  which 
connejft  the  ganglia  together,  send  out  branches  to  the  cranial  and 
spinal  nerves,  and  form  networks  in  the  vicinity  of  the  stomach 
and  other  large  organs.  A  considerable  portion  of  them  also 
follows  the  distribution  of  the  lar^e  and  small  blood-vessels,  in 
which  the  muscular  tunic  appears.  Branches  also  ascend  into  the 
head,  and  supply  the  muscles  of  the  eye  and  ear,  and  other  organs 
of  sense. 

18.  In  this  manner  the  various  regions  of  the  body  are  associ- 
ated with  each  other  by  a  nervous  apparatus,  which  is  only 
indirectly  connected  with  the  brain  and  spinal  cord,  and  thus 
it  is  arranged  that  the  most  widely  separated  organs  of  the  body 
are  brought  into  close  and  active  sympathy  with  each  other,  so  that 
"if  one  member  suffers,  all  the  other  members  suffer  with  it." 
From  this  fact,  the  name  sympathetic  system,  or  the  great  sympa- 
thetic nerve,  has  been  given  to  the  complicated  apparatus  we  have 
briefly  described.  Blushing  and  pallor  are  caused  by  mental 
emotions,  as  modesty  and  fear,  which  produce  opposite  conditions 
of  the  capillaries  of  the  face  by  means  of  these  sympathetic  nerves. 
(Read  Note  3.) 

slowly  made,  and  always  being  more  highly  perfected,  by  means  of  which,  with 
each  impression  from  without,  there  arises  in  the  brain  a  picture  of  the  spot 
upon  the  skin  where  the  irritation  has  taken  place.  Now,  if  an  irritation 
were  to  pass  from  one  nerve  fibre  to  another,  it  is  very  plain,  the  brain  could 
not  tell  the  place  from  which  it  came,  and  could  not  localize  impressions 
received  from  the  world  about  us." — Bernstein's  Five  Senses  of  Man. 

3.  The  Wonderful  Operations  of  the  Sympathetic  System.— 
Blushing  or  "Shame-redness." — "A  blow  upon  the  head  will  knock  a 
man  senseless,  but  he  still  lives  and  survives ;  a  blow  of  like  violence  upon  the 
pit  of  the  stomach  is  followed  by  instant  death,  because  the  great  centre  of  the 
organic  nerves  lies  there,  and  the  vital  actions  are  suspended  by  the  blow,  so 
that  the  system  never  lives  to  recover,  but  abolition  of  function  and  of  life  at 
once  follows.  Other  actions  also  belong  to  this  organic  nervous  system.  It 


18.  Association  of  the  various  regions  of  the  body  ?    If  one  Member  suffers  ?    Blushing! 


192  THE   NERVOUS   SYSTEM. 

19.  The  Properties  of  Nervous  Tissue. — We  have  seen  that 
in  all  parts  of  this  system  there  are  only  two  forms  of  nervous 
tissue,  namely,  the  gray  substance  and  the  white  substance,  so 
called  from  their  difference  of  color  as  seen  by  the  naked  eye ;  or 
the  nerve-cell,  and  the  nerve-fibre,  so  called  from  their  microscopic 
appearance.     Now  these  two  tissues  are  not   commonly  mingled 
together,  but  either  form  separate  organs  or  distinct  parts  of  the 
same  organs.     This  leads  us  to  the  conclusion  that  their  respective 
uses  are  distinct.     And  tl^is  proves  to  be  the  simple  fact ;  wherever 
we  find  the  gray  substance,   we  must  look  upon  it  as  perform- 
ing an  active  part  in  the  system — that  is,  it  originates  nervous 
impulses ;  the  white  matter,  on  the  contrary,  is  a  passive  agent,  and 
serves  merely  as  a  conductor  of  nervous  influences.     Accordingly, 
the  nervous  centres,  composed  so  largely  of  the  gray  cells,  are  the 
great  centres  of  power,  and  the  white  fibres  are  simply  the  instru- 
ments by  which  the  former  communicate  with  the  near  and  distant 
regions  of  the  body  under  their  control. 

20.  We  may  compare  the  brain,  then,  to  the  capital,  or  seat  of 
fC\  *•  government,  while  the  various  ganglia,  including  the  gray  matter  of 

the  cord,  like  so  many  subordinate  official  posts,  are  invested  with 
authority  over  the  outlying  provinces;  and  the  nerves,  with  the 

controls  the  calibre  of  the  blood-vessels,  for  which  end  filaments  run  along 
each  of  them.  The  body  temperature  is  maintained  by  the  production  and 
dispersion  of  heat  thus  regulated,  a  continuous  oscillation  going  on  betwixt 
the  internal  vessels  and  those  of  the  skin.  It  is  connected  with  the  emotions ; 
and  so  the  heart  beats  perceptibly  with  excitement,  and  the  maiden's  cheek 
blushes  before  words  that  should  never  be  spoken,  or  thoughts  that  should 
never  arise.  The  momentary  dilatation  of  the  vessels  of  the  skin  constitutes 
the  blush  (in  the  German,  'shame-redness'),  which  is  not  confined  to  the  face, 
though,  of  course,  it  is  only  seen  there — the  body  being  hid  by  the  clothes. " — 
Pother  gill  on  the  Maintenance  of  Health. 

"There  is  an  old  tradition  that  when  the  executioner  of  Charlotte  Corday 
lifted  her  severed  head  high  in  air,  and  smote  the  face  with  his  hand,  the 
cheeks  were  seen  to  resent  the  insult  with  a  "blush.  This  reddening  is  not 
impossible,  for  a  decapitated  head  certainly  may  exhibit,  for  a  time,  certain 
reflex  movements.  But  whether  sensibility  is  retained  cannot  be  known." 

19.  Properties  of  nervous  tissue?    Office  of  the  gray  substance  ?    Of  the  white?    The 
nervous  centres  ?    White  fibres  ? 

20.  What  comparison  is  made  between  the  brain  and  the  nation's  capital  ?    The  vital 
property,  excitability  t    What  example  is  given  ? 


THE   NERVOUS   SYSTEM.  193 

white  matter  of  the  cord,  are  the  highways  over  which  messages  go 
and  return  between  these  provinces  and  the  local  or  central  govern-  - 
ments.  But  both  forms  of  nervous  tissue  possess  the  same  vital 
property  called  excitability,  by  which  term  is  meant  that,  when  a 
nerve-cell  or  fibre  is  stimulated  by  some  external  agent,  it  is  capa- 
ble of  receiving  an  impression,  and  of  being  by  it  excited  into 
activity.  A  ray  of  light,  for  example,  falling  upon  one  extremity 
of  a  fibre  in  the  eye,  excites  it  throughout  its  whole  length;  and  its 
other  extremity  within  the  brain,  communicating  with  a  nerve-cell, 
the  latter  in  its  turn  is  excited,  and  the  sensation  of  sight  is  pro- 
duced. (Read  Note  4. )  J 

21.  What  sort  of  change  takes  place  in  the  nervous  tissue  when 
its  excitability  is  aroused,  is  not  known ;  certainly  none  is  visible. 
On  this  account,  it  has  been  thought  by  some  that  the  nerve-fibre 
acts  after  the  manner  of  a  telegraph-wire ;  that  is,  it  transmits  its 
messages  without  undergoing  any  material  change  of  form.  But 
though  the  comparison  is  a  convenient  one,  it  is  far  from  being 
strictly  applicable,  and  the  notion  that  nerve-force  is  identical  with 
electricity  has  been  fully  proved  to  be  incorrect. 

4.  The  Relations  of  the  Brain  and  Sympathetic  Nerve. — "  Buried 

in  the  hidden  recesses  of  the  body,  between  the  spinal  column  and  the  great 
organs  of  nutrition,  there  is  a  double  row  of  small  knots  of  nervous  sub- 
stance, bound  together  by  a  series  of  nerves  running  from  one  to  another, 
in  succession,  from  the  neck  to  the  base  of  the  column.  The  whole 
appears  like  a  long,  fine  cord,  with  knots  at  various  distances — a  collec- 
tion of  little  brains,  if  I  may  use  a  rather  crude  expression.  It  is,  as  the 
Swiss  would  say,  the  'great  council'  of  this  federative  republic,  which  counter- 
poises that  cerebral  royalty  within  us.  It  has  been  well  named  the  great 
sympathetic  nerve,  and  this  it  is  which  makes  the  laws  by  which  our 
interior  life  is  governed.  The  nutritive  apparatus  of  a  country,  its  com- 
merce, its  industry,  the  incessant  labor  of  its  citizens,  by  which  the 
public  wealth  is  built  up — and  also  let  us  add,  the  throbs  of  the  national 
heart — all  this  the  sympathetic  system  full  jlainly  shows  us  should  be  left  to 
itself.  It  would  be  a  fine  affair  if  the  brain  had  to  watch  over  the  service  of 
the  stomach,  or  if,  at  its  convenience,  it  regulated  the  movements  of  the 
master  wh«  disposes  of  its  life.  Besides,  what  would  become  of  the  poor  body, 
if  the  least  drowsiness  attacked  the  universal  centre  ?  Happy  is  it  for  us — and 
let  us  not  be  slow  to  own  it — that  nature  has  armed  herself  against  these  en- 
croachments of  power." — Mace's  The  Little  Kingdom. 

21.  Change  in  the  nervous  tissues  I    Nerve  force  and  electricity  ? 

9 


194  THE    NERVOUS    SYSTEM. 

22.  The  Functions  of  the  Nerves. — The  nerves  are  the  in 
struments  of  the  two  grand  functions  of  the  nervous  system — Sensa- 
tion and  Motion.     They  are  not  the  true  centres  of  either  function, 
but  they  are  the  conductors  of  influences  which  occasion  both.     If 
the  nerve  in  a  limb  of  a  living  animal  be  laid  bare,  and  irritated  by 
pinching,  galvanizing,  or  the  like,  two  results  follow,  namely:  the 
animal  experiences  a  sensation,  that  of  pain,  in  the  part  in  which 
the  nerve  is  distributed,  and  the  limb  is  thrown  into  convulsive 
action.     When  a  nerve  in  a  human  body  is  cut  by  accident,  or 
destroyed  by  disease,  the  part  in  which  it  ramifies  loses  both  sensa- 
tion and  power  of  motion;  or,  in  other  words,  it  is  paralyzed.     We 
accordingly  say  that  the  nerves  have  a  two-fold  use — a  sensory  and 
a  motor  function. 

23.  If  a  nerve  that  has  been  exposed  be  divided,  and  the  inner 
end,  or  that  still  in  connection  with  the  nerve-centres  be  irritated, 
sensation  is  produced,  but  no  movement  takes  place.     But  if  the 
outer  end,  or  that  still  connected  with  the  limb,  be  irritated,  then 
no  pain  is  felt,  but  muscular  contractions  are  produced.     Thus  we 
prove  that  there  are  two  distinct  sets  of  fibres  in  the  nerves — one 
of  which,  the  sensory  fibres,  conduct  toward  the  brain,  and  anotner, 
the  motor  fibres,  conduct  to  the  muscles.     The  former  may  be  said 
to  begin  in  the'  skin  and  other  organs  and  end  in  the  brain,  while 
the  latter  begin  in  the  nervous  centres  and  end  in  the  muscles. 
They  are  like  a  double  line  of  telegraph  wires,  one  for  inquiries, 
the  other" for  responses. 

24.  We  have  already  spoken  of  the  two  roots  of  the  spinal 
nerves,  called,  from  their  points  of  origin  in  the  spinal  cord,  the 
anterior  and  posterior  roots.     These  have  been  separately  cut  and 
irritated  in  the  living  animal,  and  it  has  been  found  that  the  pos- 
terior root  contains  only  sensory  fibres,  and  the  anterior  root  has  only 
motor  fibres.     So  that  the  nerves  of  a  limb  may  be  injured  in  such 
a  way  that  it  will  retain  power  of  motion  and  yet  lose  sensation ;  or 
the  reverse  condition,  feeling  without  motion,  may  exist.     Between 

22.  Functions  of  the  nerves?     In  the  case  of  the  nerve  of  a  living  animal?    Of  the 
human  body  ? 

23.  If  an  exposed  nerve  be  divided  ?    What  is  proved  ?    The  course  of  the  sensory  sot 
of  fibres  ?    Of  the  motor  set  ?    To  what  are  they  likened  ? 

24.  The  two  roots  of  the  spinal  nerves?    What  has  been  found?    Difference  of  the  two 
sorts  of  fibres  ?    Result  of  their  union  I 


THE    NERVOUS    SYSTEM.  195 

these  two  sorts  of  fibres  no  difference  of  structure  can  be  found ; 
and  where  they  have  joined  to  form  a  nerve,  it  is  impossible  to  dis- 
tinguish one  sort  from  the  other. 

J2&-  Occasionally  a  nerve  is  so  compressed  as  to  be  temporarily 
unable  to  perform  its  functions :  a  transient  paralysis  then  takes 
place.  This  is  the  case  when  the  leg  or  arm  "  gets  asleep,"  as  it  is 
expressed.  When  such  is  the  condition  with  the  leg,  and  the  per- 
son suddenly  attempts  to  walk,  he  is  liable  to  fall,  inasmuch  as  the 
motor  fibres  cannot  convey  orders  to  the  muscles  of  the  limb.  An- 
other fact  is  observed :  there  is  no  sensation  in  this  nerve  at  the 
point  of  its  compression ;  but  the  whole  limb  is  numb,  and  tingling 
sensations  are  felt  in  the  foot — the  point  from  which  the  sensory 
fibres  arise. 

26.  This  illustrates  the  manner  in  which  the  brain  interprets  all 
injuries  of  the  trunk  of  a  nerve.     Sensation  or  pain  is  not  felt  at 
the  point  of  injury,  but  is  referred  to  the  outer  extremities  of  the 
nerve,  where  impressions  are  habitually  received.     This  is  the  rea- 
son why,  after  a  limb  has  been  amputated  by  the  surgeon,  the  pa- 
tient appears  to  suffer  pain  in  the  member  that  has  been  severed 
from  the  body ;  while  some  form  of  irritation  at  the  end  of  the 
nerve  in"  the  wound,  or  stump,  is  the  real  source  of  his  distress. 
Again,  when  the  "  funny-bone  " — that  is,  the  ulnar  nerve  at  the 
elbow — is  accidentally  struck,  the  tingling  sensations  thus  produced 
are  referred  to  the  outer  side  of  the  hand  and  the  little  finger,  the 
parts  to  which  that  nerve  is  distributed. 

27.  All  the  spinal  nerves,  and  two  from  the  brain,  are  concerned 
in  both  sensation  and  motion.     Of  the  remainder  of  the  cranial 
nerves,  some  are  exclusively  motor,  others  exclusively  sensory ;  and 
still  others  convey,  not  ordinary  sensations,  but  special  impressions, 
such  as  sight,  hearing,  and  smell,  which  we  have  yet  to  consider. 
However  much  the  functions  of  the  nerves  seem  to  vary,  there  is 
but  little  difference  discoverable  in  the  nerves  themselves,  when 
examined  under  the  microscope.     Whatever  difference  exists  must 

25.  Transient  paralysis?    When  such  is  the  case  with  the  leg?    What  other  fact  is  ob- 
served ? 

26.  What  does  this  illustrate?    Sensation?    The  feeling  after  a  limb  has  been  amputated ? 
Striking  of  the  "  funny-bone  ?  " 

27.  The  spinal  nerves,  and  two  from  the  brain?    Of  the  remainder?    Difference  in  the 
nerves  ?    How  accounted  fc r?    The  rate  of  conduction  along  a  nerve?    As  compared  with 
electricity? 


196  THE    NERVOUS   SYSTEM. 

be  accounted  for  in  consequence  of  the  nerves  communicating  with 
different  portions  of  the  gray  matter  of  the  brain.  The  rate  of  mo- 
tion of  a  message,  to  or  from  the  brain  along  a  nerve,  has  been 
measured  by  experiment  upon  the  lower  animals,  and  estimated  in 
the  case  of  man  at  about  two  hundred  feet  per  second.  As  com- 
pared with  that  of  electricity,  this  is  a  very  slow  rate,  but,  in  respect 
to  the  size  of  the  human  body,  it  is  practically  instantaneous.  (Read 
Note  5.) 

28.  The  Functions  of  the  Spinal  Cord. — As  the  anterior  and 
posterior  roots  of  the  spinal  nerves  have  separate  functions,  so  the 
anterior  and  posterior  columns  of  the  cord  are  distinct  in  function. 
The  former  are  concerned  in  the  production  of  motion,  the  latter  in 
sensation.  If  the  cord  be  divided,  as  before  in  the  case  of  the 
nerve,  it  is  found  that  the  parts  below  the  point  of  injury  are  de- 
prived of  sensation  and  of  the  power  of  voluntary  motion  on  both 
>eides  of  the  body — a  form  of  paralysis  which  is  called  paraplegia. 
AA  29.  This  form  of  disease — paraplegia — is  sometimes  seen  among 
n  inen,  generally  as  the  result  of  a  fall,  or  some  other  severe  accident, 
by  which  the  bones  of  the  spine  are  broken,  and  the  cord  is  crushed, 
or  pierced  by  fragments  of  bone.  The  parts  which  are  supplied  by 
nerves  from  the  cord  above  the  point  of  injury  are  as  sensitive 
and  mobile  as  before.  The  results  are  similar,  whether  the  division 
happens  at  a  higher  or  lower  portion  of  the  spinal  cord ;  but  the 
danger  to  life  increases  proportionally  as  the  injury  approaches 
the  brain.  When  it  occurs  in  the  neck,  the  muscles  of  inspiration 
are  paralyzed,  since  they  are  supplied  by  nerves  issuing  from  that 

5.  The  Speed  of  Sensation  and  Thought. — "The  rate  of  nervous  and 
mental  action  is  not  the  same  in  all  individuals.  In  comparing  the  records 
made  by  astronomers,  it  has  been  found  that  an  appreciable  difference  exists 
in  the  rapidity  with  which  the  same  occurrence  may  be  noted  by  different  ob- 
servers. This  is  known  as  the  'personal  equation,'  and  is  allowed  for  with  the 
greatest  nicety  in  the  making  up  of  astronomical  reports.  With  very  delicate 
apparatus  for  marking  time,  the  various  nervous  impulses  have  been  observed  ; 
from  forty  to  a  hundred  feet  in  a  second  are  the  estimates  of  different  experi- 
ments as  to  the  speed  of  sensation  ;  or,  as  it  has  been  expressed,  it  would  take 
a  full-grown  whale  a  second  to  feel  the  stroke  of  a  harpoon  in  his  tail. " 

28.  Functions  of  the  anterior  and  posterior  columns  of  the  cord  ?   If  the  cord  be  divided! 

29.  Paraplegia  ?    Result  and  danger  to  life  ?    When  the  injury  occurs  in  the  neck  ? 


/  THE   NERVOUS    SYSTEM.  197 

ion ;  and  as  a  result  of  this  paralysis,  the  lungs  are  unable  to 
act,  and  life  is  speedily  brought  to  a  close. 

30.  When  the  spinal  cord  of  an  animal  has  been  cut,  in  experi- 
ment, it  may  be  irritated  in  a  manner  similar  to  that  alluded  to 
when  considering  the  nerves.     If,  then,  the  upper  cut  surface  be 
excited,  it  is  found  that  pain,  referable  to  the  parts  below  the  cut, 
is  produced ;  but  when  the  lower  cut  surface  is  irritated,  no  feeling 
is  manifested.     So  we  conclude  that  in  respect  to  sensation,  th. 
spinal  cord  is  not  its  true  centre,  but  that  it  is  merely  a  conductor, 
and  is  therefore  the  great  sensory  nerve  of  the  body.     When  the 
lower  surface  of  the  cut  is  irritated,  the  muscles  of  the  parts  below 
the  section  are  violently  contracted.     Hence  we  conclude  that,  in 
respect  to  the  movements  ordered  by  the  will,  the  spinal  cord  is  not 
their ,  source,  but  that  it  acts  only  as  a  conductor,  and  is,  accord- 
ingly j  the  great  motor  nerve  of  the  body. 

31.  Direction  of  the  Fibres  of  the  Cord. — If  one  lateral  half 
of  the  spinal  cord  be  cut,  or  injured,  a  very  singular  fact  is  observed. 
All  voluntary  power  over  the  muscles  of  the  corresponding  half  of 
the  body  is  lost,  but  the  sensibility  of  that  side  remains  undimin- 
ished.     This  result  shows  that  the  motor  fibres  of  the  cord  pursue 
a  direct  course,  while  its  sensory  fibres  are  bent  from  their  course. 
And  this  has  been  proved  to  be  the  fact ;  for  immediately  after  the 
posterior  roots — the  conductors  of   sensory  impressions — join  the 
posterior  columns,  they  enter  the  gray  matter  of  the  cord,  and  pass- 
ing over,  ascend  to  the  brain  on  the  opposite  side,  f  Accordingly, 
the  sensory  fibres  from  the  right  and  left  sides  interlace  each  other 
in  the  gray  matter ;  this  arrangement  has  been  termed  the  decussa- 
tion,  or  crossing  of  these  fibres.     This  condition  serves  to  explain 
how  a  disease  or  injury  of  the  cord  may  cause  a  paralysis  of  motion 
in  one  leg,  and  a  loss  of  sensation  in  the  other. 

32.  The  direction  of  the  anterior,  or  motor  columns  of  the  cord, 
is  downward  from  the  brain.     In  the  cord  itself,  the  course  of  the 
motor  fibres  is  for  the  most  part  a  direct  one ;  but  in  the  medulla 
oblongata,  or  upper  extremity  of  the  cord,  and  therefore  early  in 

30.  Experiment  of  cutting  the  spinal  cord  of  an  animal?    What  inference  is  drawn  ? 

31.  What  singular  fact  is  noticed  ?    What  does  the  result  show  ? 

32.  Direction  of  the  anterior  or  motor  columns  ?    In  the  cord  itself?    In  the  medulla 
oblongata?    The  decussation T 


198  THE    NERVOUS   SYSTEM. 

their  career,  these  fibres  cross  from  side  to  side  in  a  mass,  and  not 
separately,  as  in  the  case  of  the  posterior  fibres  just  mentioned. 
This  arrangement  is  termed  the  decussation  of  the  anterior  columns 
of  the  medulla. 

33.  From  this  double  interlacing  of  fibres  results  a  cross  action 
between   the    original  and  terminal  extremity  of  all  nerve-fibres 
which  pass  through  the  medulla — namely,  those  of  all  the  spinal 
nerves.     Consequently,  if  the  right  hand  be  hurt,"  the  left  side  of 
the  brain  feels  the  pain ;  and  if  the  left  foot  move,  it  is  the  right 
hemisphere  which  dictates  its  movement.     For  the  same  reason, 
when  a  loss  of  sensation  and  power  of  motion  affecting  the  right 
side  of  the  body  alone  is  observed,  the  physiologist  understands  that 
the  brain  has  been  invaded  by  disease  upon  its  left  side.     This 
affection  is  termed  hemiplegia,  or  the  "  half-stroke."   The  full-stroke, 
which  often  follows  the  rupture  of  a  blood-vessel  in  the  brain,  is 
commonly  called  paralysis. 

34.  The  Reflex  Action  of  the  Cord. — We  have  already  con- 
sidered the  cord  as  the  great  motor  and  sensory  nerve  of  the  body, 
but  it  has  another  and  extremely  important  use.     By  virtue  of  the 
gray  matter,  which  occupies  its  central  portion,  it  plays  the  part  of 
an  independent  nerve  centre.     The  spinal  cord  not  only  conducts 
some  impressions  to  the  brain,  but  it  also  arrests  others ;  and,  as  it 
is  expressed,  "  reflects "  them  into  movements  by  its  own  power. 
This  mode  of  nervous  activity  is  denominated  the  reflex  action  of 
the  cord. 

35.  A  familiar  example  of  this  power  of  the  cord  is  found  in  the 
violent  movements  which  agitate  a  fowl  after  its  head  has  been  cut 
off.     The  cold-blooded  animals  also  exhibit  reflex  movements  in  an 
astonishing  degree.     A  decapitated  centipede  will  run  rapidly  for- 
ward, and  will  seemingly  strive  to  overturn,  or  else  climb  over 
obstacles  placed  in  its  way.     A  frog  similarly  mutilated  will  sustain 
its  headless  body  upon  its  feet,  in  the  standing  posture,  just  as  it 

.might  do  if  it  were  still  alive.     If  pushed  over,  it  will  regain  its 
feet ;  and  if  the  feet  are  irritated,  it  will  jump  forward.     There  can 

33.  Result  of  the  double  interlacing  of  fibres  ?    Where  is  the  seat  of  pain  when  the  right 
hand  is  hurt  ?    The  moving  of  the  foot  ?    Loss  of  sensation  in  one  side  of  the  body  ? 

34.  What  other  important  use  has  the  cord  ?    What  is  the  activity  denominated  ? 
85.  Example  of  the  fowl  ?    Centipede?    Frog?    What  do  they  prove  ? 


THE   NERVOUS    SYSTEM.  199 

be  no  doubt  that,  in  the  lower  animals,  movements  may  take  place 
which  are  completely  divorced  from  the  will,  sensation,  and  con- 
iciousness;  for  in  those  animals,  as  well  as  in  man,  these  faculties 
have  their  principal  seat  within  the  brain. 

36.  An  irritation  is  necessary,  in  most  instances,  to  awaken  re- 
flex movements.     In  the  case  of  the  decapitated  fowl,  its  muscles 
are  excited  to  convulsive  action  by  reason  of  its  being  thrown  upon 
the  hard  ground  and  roughly  handled.     Let  it  be  treated  differently, 
and  the  convulsions  will  not  take  place  :  let  it  be  laid  gently  upon 
soft  cotton,  and  the  body  will  remain  comparatively  quiet.     It  may 
comfort  some  people  to  know  that  the  convulsions  which  follow 
decapitation  are  not  attended  with  pain,  nor  are  they  a  necessary 
part  of  the  "  act  of  death,"  as  some  suppose. 

37.  In  the  human  body,  likewise,  actions  are  excited  that  are 
entirely  distinct  from  the  ordinary  voluntary  efforts.     It  is  not  per- 
missible, desirable,  nor  even  necessary  to  decapitate  a  man  that  the 
body  may  be  disconnected  from  his  brain,  in  order  to  test  the  effect 
of  irritation  upon  the  spinal  cord — although  the  bodies  of  beheaded 
criminals  have  been  experimented  upon,  and  caused  to  move  by 
powerful  galvanic  batteries.      Such  experiments  are  rendered  un- 

•  -  necessary  by  the  occurrence  of  certain  deplorable  cases  of  disease 
and  injury,  which  effectually  sever  all  communication  between  the 
brain  and  a  large  part  of  the  body. 

38.  Thus,  the   cord  by  an  accident  may  be  so  far  injured  as  to 
•  terminate  all  sensation  and  voluntary  motion  in  the  lower  half  of 

body,  the  patient  seeming  lifeless  and  powerless  from  the  waist 
downward.  And  yet,  by  tickling  or  pinching  either  foot,  the  leg  of 
the  same  side  may  be  made  to  jerk,  or  even  to  kick  with  consider- 
able force ;  but,  unless  the  patient  is  observing  his  limbs,  he  is 
wholly  unconscious  of  these .  movements,  which  are,  therefore,  per- 
formed independently  of  the  brain.  And  they  are  in  no  wise  due  to 
the  muscles  of  the  limb;  for,  if  the  cord  itself  become  diseased 
below  the  point  of  injury,  the  muscles  cease  to  contract. 

39.  For  the  production  of  this  form  of  nervous  action,  three 

36.  What  is  necessary  in  most  cases  to  awaken  reflex  movements  ?    In  the  case  of  the 
fowl  ?    Convulsions  which  follow  decapitation  ? 

37.  Actions  in  the  human  body  distinct  from  voluntary  efforts  ? 

3$.  Reflex  action  after  injury  of  the  cord  ?    Why  not  due  to  the  muscles  ? 


200  THE   NERVOUS   SYSTEM. 

things  are  requisite — (1)  a  nerve  to  conduct  messages  from  the 
surface  of  the  body,  one  of  that  variety  formerly  described  as  sen- 
sory, but  which  are  now  known  to  be  incapable  of  awakening  sen- 
sation ;  (2)  a  portion  of  uninjured  spinal  cord,  which  shall  reflect  or 
convert  impressions  into  impulses ;  and  (3)  a  motor  nerve  to  con- 
duct impulses  outward  to  the  muscles.  The  power  of  the  cord  to 
enforce  reflex  acts  resides  in  the  gray  matter,  into  which  the  reflex 
nerves  enter  and  from  which  they  depart,  by  means  of  their  pos- 
terior and  anterior  roots  respectively. 

40.  The  Uses  of  the  Reflex  Action. — The  reflex  activity  of 
the  cord  is  exhibited  in  the  healthy  body  in  many  ways,  but  since 
it  is  never  accompanied  with  sensation,  we  do  not  readily  recognize 
it  in  our  own  bodies.     Reflex  movements  are  best  studied  in  the 
cases  of  other  persons,  when  the  conditions  enable  us  to  distinguish 
between  acts  that  are  consciously,  and  those  that  are  unconsciously 
performed.     For  example,  if  the  foot  of  a  person  soundly  asleep  be 
tickled  or  pinched,  it  will  be  quickly  withdrawn  from  the  irritation. 

41.  Similar  movements  may  be  observed  in  cases  where  the  con- 
sciousness and  sensation  are  temporarily  obliterated  by  disease,  or 
by  means  of  narcotic  poisons.     If  the  arm  of  a  person  who  has  been 
rendered  insensible  by  chloroform  be  raised,  and  then  allowed  to 
fall,  it  will  be  noticed  that  the  limb  does  not  drop  instantly,  like  a 
lifeless  member,  but  a  certain  amount  of  rigidity  remains  in  its 
muscles,  which  resists  or  breaks  the  force  of  its  descent.     Again, 
when  a  substance  like  melted  sealing-wax,  or  a  heated  coin,  falls 
upon  the  hand,  the  limb  is  snatched  away  at  once,  even  before  the 
feelingrof  pain  nas  been  recognized  by  the  brain.     When  jolted  in 
a  rapidr^mcrvmg  car,  we  involuntarily  step  forward  or  backwardj 
so  as  to  preserve  the  centre  of  gravity  of  the  body. 

42.  These  and  similar  acts  are  executed  by  the  same  mechanism 
.as  that  previously  described  in  the  case  of  paralysis  from  an  injury 

of  the  spinal  cord.     The  muscles  thus  called  into  play  are  those 
which  are  ordinarily  under  the  sway  of  the  will,  but  which  in  these 


89.  What  are  the  requisites  for  the  production  of  this  form  of  nervous  action  ? 

40.  Why  do  we  not  readily  recognize  the  reflex  activity  of  the  cord  in  our  own  bodies  1 
How  best  studied  in  others  ?    Example  f 

41.  Similar  movements  ?    Arm  of  a  person  ?    Melted  wax  or  heated  coin  on  the  hand  ? 

42.  Result  oPhealthful  reflex  activity?    When  may  the  reflex  energy  be  deficient? 


THE    NERVOUS    SYSTEM.  201 

cases  act  through  this  reflex  action  of  the  cord,  altogether  independ- 
ently of  the  will.  A  healthful  reflex  activity  produces  an  elasticity, 
or  "tone,"  in  the  voluntary  muscular  system,  which  in  a  great 
measure  explains  the  existence  in  the  young  and  vigorous  of  a  feel- 
ing of  buoyancy  and  reserve  power.  Its  possessor  is  restlessly 
active,  and  it  may  appropriately  be  said  of  him,  "  he  rejoiceth  as  a 
strong  man  to  run  a  race."  But  this  reflex  energy  may  be  deficient. 
This  is  true  when  the  blood  is  poor  and  wanting  in  its  solid  ingre- 
dients, or  the  circulation  is  feeble;  the  muscles,  then,  are  flabby 
and  weak,  and  the  person  himself  is  said  to  be  "  nerveless,"  or  in- 
disposed to  exertion.  Shivering  from  cold  and  trembling  from  fear 
may,  in  part,  be  referred  to  a  temporary  loss  of  tone,  resulting  from 
a  powerful  impression  upon  the  brain.  (Read  Note  6.) 

43.  An  excess  of  this  activity  may  also  be  observed  in  disease. 
In  this  condition,  the  excitability  of  the  cord  is  unnaturally  aroused 

6.  On  Nervous  Health,  or  Tone. — "That  state  of  general  vigor, 
which  we  call  'tone,'  depends  upon  the  healthy  action  of  the  nervous  centres. 
It  consists  in  the  habitual  moderate  contraction  of  the  muscles,  due  to  a  con- 
stant stimulus  exerted  on  them  by  the  cord,  and  is  valuable  less  for  itself  than 
as  a  sign  of  a  sound  nervous  balance.  Tone  is  maintained  partly  by  healthful 
impressions  radiated  up.on  the  spinal  cord  through  the  nerves  from  all  parts  of 
the  body,  and  partly  by  the  stimulus  poured  down  upon  it  from  the  brain. 
So  it  is  disturbed  by  whatever  conveys  irritating  or  depressing  influences  in 
either  direction.  A  single  injudicious  meal,  a  single  sleepless  night,  a  single 
passion  or  piece  of  bad  news,  will  destroy  it.  On  the  other  hand,  a  vivid  hope, 
a  cheerful  resolve,  an  absorbing  interest  will  restore  it  as  if  by  magic.  For  in 
man,  these  lower  officers  in  the  nervous  hierarchy  draw  their  very  breath  ac- 
cording to  the  bidding  of  the  higher  powers.  But  the  dependence  of  the  higher 
on  the  lower  is  no  less  direct.  The  mutual  action  takes  place  in  each  line.  A 
chief  condition  of  keeping  the  brain  healthy  is  to  keep  these  unconscious 
nervous  functions  in  full  vigor,  and  in  natural  alternations  of  activity  and  re- 
pose. We  see  evidence  of  this  law  in  the  delightful  effect  of  a  cheerful  walk 
after  a  depressed  or  irritated  state  of  mind.  Every  part  of  the  nervous  system 
makes  its  influence  felt  by  all  the  rest.  A  sort  of  constitutional  monarchy 
exists  within  us  ;  no  power  in  this  small  state  is  absolute,  or  can  escape  the 
checks  and  limitations  which  the  other  powers  impose.  Doubtless  the  Brain 
is  King,  but  Lords  and  Commons  have  their  seats  below  and  guard  their  privi- 
lege with  jealous  zeal.  If  the  '  constitution '  of  your  personal  realm  is  to  be 
preserved  intact,  it  must  be  by  the  efforts  of  each  part,  lawfully  directed  to  a 
common  end. " — Hinton  on  Health  and  Us  Conditions. 


02     \l  THE    NERVOUS   SYSTEM. 

and  frequent  and  violent  movements  of  the  limbs  and  body,  called 
convulsions,  are  the  result.  The  convulsions  of  young  children, 
and  the  nervous  agitation  of  chorea,  or  St.  Yitus's  dance,  are  reflex 
in  character,  as  are  also  the  symptoms  attending  poisoning  by 
hnine,  and  those  terrible  diseases,  tetanus,  or  "locked  jaw," 
hydrophobia.  The  severity  of  the  convulsions  is  not  the  same 
rn  all  cases  of  these  disorders;  but,  in  those  last  mentioned,  the 
most  violent  spasmodic  movements  are  provoked  by  the  slightest 
form  of  irritation — such  as  the  sound  of  pouring  water,  the  sight  of 
glittering  object,  the  glancing  of  a  mirror,  the  contact  of  cool 
air,  or  even  the  touch  of  the  bed-clothes. 

44.  Another  variety  of  reflex  motions  takes  place  hi  certain  in- 
voluntary muscles,  and  over  these  the  cord  exercises  supreme  con- 

irol.  They  are  principally  those  movements  which  aid  the  perform- 
ance of  digestion  and  nutrition,  the  valve-action  of  the  pylorus, 
and  other  movements  of  the  stomach  and  intestines.  In  these 
movements  the  mind  shares  no  part.  And  it  is  well  that  this  is  so ; 
for,  since  the  mind  is  largely  occupied  with  affairs  external  to  the 
body,  it -acts  irregularly,  becomes  fatigued,  and  needs  frequent  rest. 
The  spinal  cord,  on  the  contrary,  is  well  fitted  for  the  form  of  work 
on  which  depends  the  growth  and  support  of  the  body,  as  it  acts 
uniformly,  and  with  a  machine-like  regularity. 

45.  These  operations  are  not  accompanied  by  consciousness ;  for, 
as  a  general  rule,  the  attention  is  only  called  to  them  when  they  be- 
come disordered.     Many  a  person  does  not  know  where  his  stomach 
is  situated  until  he  discovers  its  position  by  reason  of  a  feeling  of 
distress  within  it,  produced  by  giving  that  organ  improper  work  to 
perform.     In  this  manner  the  higher  and  nobler  faculties  of  the 
mind  are  liberated  from  the  simply  routine  duties  of  the  body,  and 
we  are  thus  left  to  direct  the  attention,  the  reason,  and  the  will  to 
the  accomplishment  of  the  great  ends  of  our  existence.     If  it  were 
otherwise,  we  could  only  find  time  to  attend  to  our  ordinary  physical 
wants. 


43.  Excess  of  this  activity  in  disease?    Hydrophobia,  etc,  ?    The  difference  in  severity  oi 
the  convulsions? 

44.  Another  variety  of  reflex  motions?    What  are  they?    What  is  stated  of  the  mind  io 
connection  with  these  movements  ? 

4S>.  Consciousness  in  these  operations?    Physical  wants? 


THE   NERVOUS   SYSTEM. 


m 


46.  The  oojects  of  the  reflex  activity  of  the  cord  are  threefold. 
In  the  first  place,  it  acts  as  the  protector  of  man  in  his  unconscious 
moments.     It  is  his  unseen  guardian,  always  ready  to  act,  never 
growing  weary,  and  never  requiring  sleep.     Nor  does  its  faithful 
action  wholly  cease  with  the  cessation  of  life  in  other  parts.     In  the 
second  place,  it  is  the  regulator  of  numerous  involuntary  motions 
that  are  necessary  to  the  nutrition  of  the  body.     Here  its  actions 
are  entirely  independent  of  the  brain,  and  are  performed  in  a  secret 
and  automatic  manner.     And,  thirdly,  it  acts  as  a  substitute,  and 
regulates  involuntary  movements  in  the  muscles  usually  under  the 
influence  of  the  will.     It  thus  takes  the  place  of  the  higher  faculties 
in  performing  habitual  acts,  and  permits  them  to  extend  their  opera- 
tions more  and  more  beyond  the  body  and  its  material  wants. 

47.  The   Functions  of  the   Medulla   Oblongata. — The  pro- 
longation  of  the  spinal  cord  within  the  skull  has  been  previously 
spoken  of  as  the  medulla  oblongata.     It  resembles  the  cord,   in 
being  composed  of  both  white  and  gray  matter,  and  in  conducting 
sensory  and  motor  influences.      It  likewise  gives  rise  to  certain 
nerves,  which  are  here  called  cranial  nerves  (from  cranium,  the 
skull).     All  except  two  of  these  important  nerves  spring  from  the 
medulla,  or  the  parts  immediately  adjoining  it ;  the  exceptions  are 
the  two  nerves  taking  part  in  the  special  senses  of  sight  and  smell, 
which  nerves  have  their  origin  at  the  base  of  the  cerebrum. 

48.  The  decussation,  or  crossing  of  the  motor  columns,  has  been 
previously  described,  when  treating  of  the  direction  of  the  nerve- 
fibres  of  the  cord ;  and  the  singular  fact  has  been  alluded  to,  that 
when  one  side  of  the  brain  is  injured,  its  effects  are  limited  to  the 
opposite  side  of  the  body.     One  more  fact  remains  to  be  observed 
in  this  connection,  namely,  this  cross  action  does  not  usually  take 
place  in  the  cranial  nerves.     Accordingly,  when  apoplexy,  or  the 
rupture  of  a  blood-vessel,  occurs  in  the  right  hemisphere  of  the 
cerebrum,  the  left  side  of  the  body  is  paralyzed,  but  the  right  side 
of  the  face  is  affected ;  this  is  because  that  part  of  the  body  is  sup- 
plied by  the  cranial  nerves. 

46.  How  many  objects  may  the  reflex  activity  be  said  to  have?    State  the  first    The 
second.    The  third. 

47.  How  does  the  medulla  oblongata  resemble  the  cord? 

48.  What  final  fact  is  observed  in  the  crossing  of  the  motor  columns  I 


s: 


204  THE   NERVOUS   SYSTEM. 

49.  A  portion  of  the  medulla  presides  over  tlie  important  func- 
tion of  respiration,,  and  from  it  arises  the  pneumogastric  nerve,  so 
called   because   its   branches  serve  both  the  lungs  and   stomach. 
The  feelings  of  hunger,  thirst,  and  the  desire  for  air  are  aroused  by 
means  of  this  nerve.     The  wounding  of  the  gray  matter  of  the 
medulla,  even  of  a  small  portion  of  it,  near  the  origin  of  the  pneu- 
mogastric nerve,  at  once  stops  the  action  of  the  lungs  and  causes 
death.     In  consequence  of  the  importance  of  this  part,  it  has  baen 
termed  the  "  vital  knot."     We  find,  also,  that  its  location  within 
the  skull  is  exceedingly  well  protected,  it  being  quite  beyond  the 
reach  of  any  ordinary*  form  of  harm  from  without. 

50.  The  Functions  of  the  Cranial  Ganglia. — The  uses  of  the 
smaller  gray  masses  lying  at  the  base  of  the  brain  are  not  well 
ascertained ;  and,  on  account  of  their  position,  so  remote  from  the 
surface,  it  would  at  first  seem  well-nigh  impossible  to  study  them. 
But,  from  the  results  following  diseases  in  these  parts,  and  from  ex- 
periments upon  inferior  animals,  they  are  becoming  gradually  better 
understood;   and  there  is  reason  to   believe   that  eventually  the 
physiological  office  of  each  part  will  be  clearly  ascertained  and  de- 
fined.    It  is  believed,  however,  but  not  absolutely  proved,  that  the 
anterior  masses,  like  the  anterior  roots  of  the  spinal  nerves  and  the 
anterior  columns  of  the  cord,  are  concerned  in  the  production  of 
motion ;  in  fact,  that  they  are  the  central  organs  of  that  function. 
The  posterior  gray  masses  are,  on  the  contrary,  supposed  to  be  the 
seat  of  sensation. 

51.  The  Function  of  the  Cerebellum. — The  function  of  the 
cerebellum,  or  "  little  brain,"  is  the  direction  of  the  movements  of 
the  voluntary  muscles.     When  this  organ  is  the  seat  of  disease  or 
injury,  it  is  usually  observed  that  the  person  is  unable  to  execute 
orderly  and  regular  acts,  but  moves  in  a  confused  manner  as  if  in  a 
state  of  intoxication.    Like  the  larger  brain,  or  cerebrum,  it  appears  to 
be  devoid  of  feeling ;  but  it  takes  no  part  in  the  operations  of  the  mind. 

52.  The  Function  of  the  Cerebrum. — The  cerebrum,  or  brain 
proper,  is  the  seat  of  the  mind ;  or,  speaking  more  exactly,  it  is  the 

49.  The  pneumogastric  nerve?    The  feelings  aroused  by  it?    The  "  vital  knot?" 

50.  The  uses  of  the  smaller  gray  masses  at  the  base  of  the  brain? 

51.  Function  of  the  cerebellum  ?    When  it  is  diseased  ? 

52.  Where  is  the  seat  of  the  mind?    The  subordination  of  the  other  organs?    The  gray 
Uiatter? 


mater 


THE   NERVOUS   SYSTEM.  205 


material  instrument  by  which  the  mind  acts  ;  and,  as  it  occupies  the 
highest  position  in  the  body,  so  it  fulfills  the  loftiest  uses.  All  the 
other  organs  are  subordinate  to  it  :  the  senses  are  its  messengers, 
which  bring  it  information  from  the  outer  world,  and  the  organs  of 
motion  are  its  servants,  which  execute  its  commands.  Here,  as  in 
the  nervous  apparatus  of  lower  grade  already  considered,  the  gray 
matter  is  the  element  of  power  ;  and  in  proportion  as  this  substance 
increases  in  extent,  and  in  proportion  to  the  number  of  convolutions 
in  the  hemispheres,  do  the  mental  faculties  expand. 

53.  There  have  been  a  few,  but  only  a  few,  men  of  distinguished 
ability  whose  brains  have  been  comparatively  small  in  size  —  the  rule 
being  that  great  men  possess  large  brains.  The  relative  weight  of 
the  brain  of  man,  as  compared  with  the  weight  of  the  body,  does 
not,  in  all  instances,  exceed  that  of  the  inferior  animals  ;  the  canary 
and  other  singing-birds  have  a  greater  relative  amount  of  nervous 
matter  than  man  ;  but  man  surpasses  all  other  creatures  in  the  size 
of  the  hemispheres  of  the  cerebrum,  and  in  the  amount  of  gray  sub- 
stance which  they  contain.  —  (Read  Notes  7 


7.  The  Alliance  of  Mind  and  Body.  —  "The  regular  routine  of  our 
daily  life  is  the  counterpart  of  the  mental  routine.     A  healthy  man  wakens  in 
the  morning  with  a  flush  of  spirits  and  energy  ;  his  first  meal  confirms  and 
reinforces  the  state.     The  mental  powers  and  susceptibilities  are  then  at  a 
maximum  ;  as  the  nutrition  is  used  up  in  the  system  they  gradually  fade,  but 
may  be  renewed  once  and  again  by  refreshment  and  brief  remission  of  toil 
Towards  the  end  of  the  day  lassitude  sets  in,  and  fades  into  the  deep  uncon- 
sciousness of  healthy  sleep.     *     *     *     The  influences  that  affect  the  body 
extend  not  only  to  the  grosser  modes  of  feeling,  and  to  such  familiar  exhibi- 
tions as  after-dinner  oratory,  but  also  to  the  highest  emotions  —  love,  anger 
aesthetic  feeling,  and  moral  sensibility.    '  Health  keeps  an  Atheist  in  the  dark. 
Bodily  affliction  is  often  the  cause  of  a  total  change  in  the  moral  nature."— 
Bain's  Mind  and  Body. 

8.  Large  Brains.  —"As  a  rule  the  size  of  the  brain  is  proportional  to  the 
mental  development  in  human  beings.     The  rule  is  not  strictly  maintained  in 
every  instance  ;  occasionally  a  stupid  man  has  a  larger  brain  than  a  clever 
man.     But  these  are  only  individual  exceptions  to  a  prevailing  arrangement 
The  following  are  the  brain  weights  of  several  distinguished  men  : 


Cuvier 64 .5  oz. 

Abercrombie 63 .     " 

Daniel  Webster 53.5  " 


Lord  Campbell 53.5  oz. 

Agassiz 53.4  " 

De  Morgan 52.7  " 


53.  What  is  stated  of  men  in  connection  with  the  size  of  their  brain?   With  the  braius  ol 
«ther  animals  ? 


" 


206  THE  NERVOUS  SYSTEM. 

54.  It  is  a  singular  fact  that  this  cerebral  substance  is  insensitive, 
and  may  be  cut  without  causing  pain.  The  removal  of  a  consider- 
able quantity  of  the  brain  has  taken  place,  as  the  result  of  accident, 
without  causing  death,  and  without  even  affecting  seriously  the 
intellect.  A  remarkable  case  of  injury  of  the  brain  is  recorded,  in 
which,  from  the  accidental  explosion  of  gunpowder  used  in  blasting 
a  rock,  the  "  taniping-iron  "  was  driven  directly  through  the  skull 
of  a  man.  This  iron  rod,  three  feet  and  seven  inches  long,  an  inch 
and  a  quarter 'in  diameter,  and  weighing  more  than  thirteen  pounds, 
entered  the  head  below  the  ear  and  passed  out  at  the  top  of  the 
skull,  carrying  with  it  portions  of  the  brain  and  fragments  of  bone. 
The  man  sustained  the  loss  of  sight  on  one  side,  but  otherwise  re- 
covered his  health  and  the  use  of  his  faculties.  Moreover,  disease 
has  occurred,  compromising  a  large  portion  of  the  brain,  without 
impairing  the  faculties  of  the  mind,  when  the  disease  was  limited  to 
one  side  only.  (Read  Note  9. ) 

"The  average  male  brain  in  Europeans  is  49.5  oz.  ;  the  female,  44  oz. 
Among  idiots  the  weights  have  run  from  27  to  8.5  oz.  The  brains  of  the 
insane  are  below  the  average  of  the  sane.  Tall  men,  as  a  rule,  have  larger 
brains  than  small  men." — Bain's  Mind  and  Body. 

9.  The  Emotions  Influence  the  Bodily  Health. — "The  exciting 
emotions  which  are  pleasurable,  such  as  joy  and  hope,  are  of  a  kind  that 
seldom  tend  to  a  dangerous  excess,  and  may  be  regarded  as  exercising  generally 
an  eminently  healthful  influence  upon  the  body.  Hilarity  is  a  great  refresher 
and  strengthener  of  life.  Laughter  is  a  wholesome  exercise,  which,  beginning 
at  the  lungs,  diaphragm,  and  connected  muscles,  is  continued  to  the  whole 
body,  *  shaking  the  sides, 'and  causing  that  jelly -like  vibration  of  the  frame  of 
which  we  are  so  agreeably  conscious  when  under  its  influence.  The  heart  beats 
more  briskly,  but  with  a  safe  regularity  of  action,  and  sends  the  blood  to  the 
smallest  and  most  distant  vessel.  The  face  glows  with  warmth  and  color,  the 
eye  brightens,  and  the  temperature  of  the  whole  body  is  moderately  raised. 
With  the  universal  pleasurable  sensation  there  comes  a  disposition  of  every 
organ  to  healthy  action.  When  hilarity  and  its  ordinary  expression  of 
laughter  become  habitual,  the  insensible  perspiration  of  the  skin  is  increased, 
the  breathing  quickened,  the  lungs  and  chest  expanded,  the  appetite  and 
digestion  strengthened,  and  nutrition  consequently  increased.  The  old  prov- 
erb, 'Laugh  and  grow  fat,'  states  a  scientific  truth.  The  influence  of 
laughter  upon  the  body  is  recognized  by  Shakespeare,  in  his  description  of  the 

54.  Sensitiveness  of  the  brain  substance  ?  The  removal  of  a  portion  of  the  brain  ?  8t»t* 
the  remarkable  case  mentioned. 


THE   NERVOUS   SYSTEM.  207 

55.  Impressions  conveyed  to  the  hemispheres  from  the  external 
world  arouse  the  mental  operations  called  thought,  emotion,  and  the 
wilL      These  are  the  godlike  attributes  which  enable  man  to  sub- 
jugate a   world,  and  afterward    cause    him  to   "  sigh  for  other 
worlds  to  conquer ;"  which  enable  him  to  acquaint  himself  with  the 
properties  of  planets  millions  of  miles  distant  from  him,  and  which 
give  him  that  creative  power  by  which  he  builds  and  peoples  the 
new  worlds  of  poetry  and  art. 

56.  All   these  mental  acts,  and  many   others,  are  developed 
through  the  action  of  the  brain ;   not  that  the  brain  and  the  mind 
are  the  same,  or  that  the  brain  secretes  memory,  imagination,  or  the 
ideas  of  truth  and  justice,  as  the  stomach  secretes  the  gastric  juice. 
But  rather,  as  the  nerve  of  the  eye,  stimulated  by  the  subtile  waves 
of  light,  occasions  the  notion  of  color,  so  the  brain,  called  into 
action  by  the  mysterious  influences  of  the  immaterial  soul,  gives  rise 
to  all  intellectual,  emotional,  and  voluntary  activities. 

57.  The  cerebrum,  according  to  our  present  knowledge  of  it,  must 
be  regarded  as  a  single  organ,  which  produces  different  results, 
according  as  it  is  acted  upon  by  the  immaterial  mind  in  different 
ways.     Recent   investigations,  however,  seem   to   prove   that  the 
faculty  of  language  is  dependent  upon  a  small  part  of  the  left 
hemisphere  of  the  cerebrum  near  the  temple.      At  least,  in  almost 
every  instance   where   this   part  is  diseased,  the   patient  can  no 
longer  express  himself  in  speech  and  writing.    (Read  Note  10.)  . 

*  spare  Cassius ' — '  Seldom  he  smiles.*  '  To  be  free-minded  and  cheerfully  dis- 
posed at  hours  of  meat,  and  sleep,  and  exercise,  is  one  of  the  best  precepts  of 
long-lasting.'  Such  is  the  testimony  of  Lord  Bacon  to  the  favorable  influence 
of  the  pleasurable  emotions  upon  the  body.  The  depressing  emotions,  such  as 
fear,  anxiety,  and  grief,  are  always  fatal  to  health,  and  frequent  causes  of 
death.  There  is  an  Eastern  apologue  which  describes  a  stranger  on  the  road 
meeting  the  Plagut  coming  out  of  Bagdad..  'You  have  been  committing 
great  havoc  there,'  said  the  traveler,  pointing  to  the  city.  •  Not  so  great,' 
replied  the  Plague.  '  I  only  killed  one-third  of  those  who  died ;  the  other 
two-thirds  killed  themselves  with  fright.'  " — The  Book  of  Health. 
iO.  Mental  Exercise  Necessary  to  Perfect  Health.— "The  im- 


65.  Thought,  emotion,  and  will  ?    What  power  do  they  give  us? 
..  .       66.  Are  the  brain  and  the  mind  identical ? 
'    /        67.  What  do  we  know  of  the  cerebrum  and  its  powers  ? 


208  ^  THE  NERVOUS  SYSTEM. 


58.  The  Reflex  Action  of  the  Brain.  —  The  reflex  function  of  the 
organs  within  the  skull  is  very  active  and  important.     Like  that  of 
the  cord,  it  protects  the  body  by  involuntary  movements,  it  regulates 
the  so-called  vegetative  acts,  and  it  takes  the  place  of  the  will  in 
controlling  the  voluntary  muscles,  when  the  attention  is  turned  in 
other  directions.     The  reflex  power  of  the  medulla  governs  the  acts 
of  respiration,  which  are  absolutely  and  continuously  essential  to 
life.     Respiration  is,  as  we  have  seen,  partly  under  the  influence  of 
the  will  ;  but  this  is  due  in  part  to  the  fact  that  respiration  is 
indirectly  concerned  in   one   of  the  animal   functions  —  that  of 
speech. 

59.  Reflex  action  also  occasions  coughing  and  sneezing,  whenever 
improper  substances  enter  the  air-passages.     Winking  is  an  act  of 
the  same  sort,  and  serves  both  to  shield  the  eyes  from  too  great  glare 
of  light,  and  to  preserve  them  by  keeping  the  cornea  moist.     Look- 
ing at  the  sun  or  other  strong  light,  causes  sneezing  by  reflex  action. 
Laughing,  whether  caused  by  tickling  the  feet  or  by  some  happy 
thought,  and  also  sobbing,  are  reflex  acts,  taking  place  by  means  of 
the  respiratory  muscles. 

60.  Certain  of  the  protective  reflex  movements  call  into  play  a 
large  number  of  muscles,  as  ia  the  balancing  of  the  body  when  walk- 

provement  of  the  memory  is  a  familiar  instance  of  an  increase  of  mental  power 
produced  by  exercise  ;  and  the  beating  sense  of  fulness  and  quickened  circula- 
tion in  the  head  induced  by  intense  study  or  thought,  shows  that  an  organic 
process  goes  on  when  the  brain  is  in  activity,  similar  to  that  which  takes  place  f 
in  the  muscular  system  under  exercise.  On  the  contrary,  when  the  organ  is 
little  used,  little  expenditure  of  its  power  and  substance  takes  place,  little  blood 
and  little  nervous  energy  are  required  for  its  support,  and,  therefore,  little  is 
sent  ;  nutrition  in  consequence  soon  becomes  languid,  and  strength  impaired. 
To  all  these  laws  the  brain  is  subject  equally  as  the  rest  of  the  body.  Frequent 
and  regular  exercise  gives  it  increased  susceptibility  of  action,  with  power  to 
eustain  it,  the  nervous  energy  acquiring  strength  as  well  as  the  vascular.  Dis- 
use of  its  functions,  or,  in  other  words,  inactivity  of  intellect  and  of  feeling, 
impairs  its  structure  and  weakens  the  several  powers  which  it  serves  to  mani- 
fest The  brain,  therefore,  in  order  to  maintain  its  healthy  state,  requires  to 
be  duly  exercised."  —  Barlow  on  Physical  Education. 


58.  The  reflex  function  of  the  organs  within  the  skull?   The  reflex  power  of  the  medulla? 
iespiration? 

59.  What  else  does  reflex  action  occasion  ?    Winking  ?    Other  examples  ? 

60.  Muscles  called  into  play  by  certain  reflex  movements  ?    The  somnambulist? 


THE    NERVOUS    SYSTEM.  209 

ing  along  a  narrow  ledge,  or  on  a  slippery  pavement.  The  dodging 
motion  of  the  recruit,  when  the  first  cannon  ball  passes  over  his 
head,  is  reflex  and  involuntary.  The  fact  that  these  involuntary 
reflex  acts  are  performed  with  great  precision,  will  explain  why 
it  is  that  accidents  seldom  befall  the  somnambulist,  or  sleep- 
walker, although  he  often  ventures  in  most  perilous  places. 

61.  Walking,  sitting,  and  other  acts  of  daily  life,  become 
automatic,  or  reflex,  from  habit :  the  mind  is  seldom  directed  to 
them,  but  delegates  their  control  to  the  medulla  and  spinal  cord. 
Thus  a  person  in  walking  may  traverse  several  miles  while  absorbed 
in  thought,  or  in  argument  with  a  companion,  and  yet  be  conscious 
of  scarcely  one  in  a  thousand  of  the  acts  that  have  been  necessary 
to  carry  his  body  from  one  point  to  another.  By  this  admirable  and 
beautiful  provision  the  mind  is  released  from  the  charge  of  the 
ordinary  mechanical  acts  of  life,  and  may  devote  itself  to  the 
exercise  of  its  nobler  faculties.  And  it  is  worthy  of  notice,  that 
the  more  these  faculties  are  used,  the  more  work  does  the  reflex 
function  assume  and  perform ;  and  thus  the  employment  of  the  one 
insures  the  improvement  of  the  other.  (Read  Notes  n  and  12.) 

11.  Automatic  Action  of  the  Brain. — "A  large  part  of  our  mental 
activity  consists  of  this  unconscious  work  of  the  brain.  There  are  many  cases 
in  which  the  mind  has  obviously  worked  more  clearly  and  more  successfully  in 
this  automatic  condition,  when  left  entirely  to  itself,  than  when  we  have  been 
cudgeling  our  brains,  so  to  speak,  to  get  the  solution.  An  instance,  well 
authenticated,  is  related  of  a  college  student ;  he  had  been  attending  a  class  in 
mathematics,  and  the  professor  said  to  his  students  one  day :  'A  question  of 
great  difficulty  has  been  referred  to  me  by  a  banker — a  very  complicated  ques- 
tion of  accounts,  which  they  have  not  themselves  been  able  to  bring  to  a 
satisfactory  issue,  and  they  have  asked  my  assistance.  I  have  been  trying,  and 
I  cannot  resolve  it.  I  have  covered  whole  sheets  of  paper  with  calculations, 
and  have  not  been  able  to  make  it  out.  Will  you  try  ?'  He  gave  it  to  them 
as  a  sort  of  problem,  and  said  he  would  be  extremely  obliged  to  any  one  who 
would  bring  him  the  solution  by  a  certain  day.  This  gentleman  tried  it  over 
\  and  over  again ;  he  covered  many  slates  with  figures,  but  did  not  succeed.  He 
was  '  put  on  his  mettle,'  and  determined  to  achieve  the  result  But  he  went 
to  bed  on  the  night  before  the  solution  was  to  be  given  in  without  having 
succeeded.  In  the  morning,  when  he  went  to  his  desk,  he  found  the  whole 


61.  What  is  said  of  walking  and  other  acts  in  connection  with  the  office  performed  by  the 
medulla  and  spinal  cord  ? 


210  THE   NERVOUS   SYSTEM. 

62.  Effects  of  Alcohol  upon  the  Brain. — The  brain  under  the 
influence  of  small  and  occasional  doses  of  alcohol  shows  no  serious 
changes  other  than  an  increased  supply  of  blood  to  the  head.  Yery 
serious  changes,  however,  result  from  the  habitual  use  of  alcohol ; 
the  brain  becomes  harder  and  tougher  than  is  natural,  and  its  cell 
elements  show  a  wasting  away,  its  substance  appears  shrunken,  and 
an  undue  amount  of  watery  fluid  fills  the  cavities  in  the  brain,  in 
order  to  make  up  the  diminished  bulk.  The  blood-vessels  of  the 
brain  are  sometimes  found  to  be  in  a  weakened  condition,  and  from 
this  various  diseased  conditions  may  follow.  (Read  Note  13.) 

problem  worked  out  and  in  his  own  hand.  He  had  risen  in  the  night  and  un- 
consciously worked  it  out  correctly,  as  the  result  proved ;  and  what  is  more 
curious  still,  the  process  was  very  much  shorter  than  any  of  his  previous 
trials." — W.  B.  Carpenter  on  Unconscious  Action. 

12.  The  Mind  Should  be  Intelligently  Cultivated.— "The  cultiva- 
tion of  the  mind  should  be  carried  on  with  judgment,  and  in  due  submission 
to  the  requirements  of  the  body.      If  study  be  the  duty  of  the  youth,  let  him 
pursue  it  diligently,  but  with  such  intervals  of  rest  and  bodily  exertion  as  may 
maintain  good  appetite  and  health. 

"The  proportion  of  hours  of  study  and  bodily  exercise  may  vary  with  the 
degree  of  mental  work,  the  healthfulness  of  the  room  and  surrounding  air,  the 
natural  strength  of  the  body,  and  the  degree  of  health ;  but  as  a  general  rule 
it  may  be  doubted  whether  any  young  person  can  sit  at  close  study  for  more 
than  two  hours  at  a  time  without  requiring  bodily  exertion  to  sustain  vital 
action,  and  rest  to  recruit  the  mind.  Two  hours'  mental  work,  and  a  quarter 
to  half  an  hour's  bodily  exercise,  will  be  quite  compatible  with  the  greatest 
progress  in  study. 

"Moreover,  it  may  be  doubted  whether  such  a  student  can  work  with 
advantage  for  more  than  eight  hours  a  day,  in  addition  to  the  intervals  of 
rest,  for  the  issue  will  not  turn  on  the  number  of  hours  devoted  to  work,  but 
the  intensity  of  the  attention  given. " — Edward  Smith  on  Health. 

13.  Trembling  due  to  Alcohol. — "Another  condition  is  trembling 
due  to  alcohol.     The  hands  are  shaky,  or  unsteady,  even  when  at  rest,  or  it 
the  hand  is  held  out  it  is  seen  to  vibrate  slightly,  or  in  more  advanced  condi- 
tion, 'shakes  like  an  aspen  leaf.'     I  have  seen  this  in  a  spirit-drinker,  a  bar- 
ber, as  almost  the  only  symptom :    he  worked  night  and  day,  in  shaving, 
and  to  'steady  his  hand,'  partook  repeatedly  of  spirits — at  first  to  relieve 
fatigue  and  then,  because  he  saw  that  if  he  discontinued,  his  hand  was  too 
shaky  to  use  the  razor.     Complete  abstinence  from  alcohol  and  strong  coffee 
quite  removed  his  tremblings  and  his  desire  for  spirits. " — Dr.  W.  S.  Greenfield. 

62.  How  is  the  brain  changed  by  alcohol  ? 


THE   NERVOUS   SYSTEM.  211 

63.  Effects   of  Alcohol   on  the  Mind. — Alcohol  produces  an 
artificial  insanity,  in  which,  according  to  the  quantity  taken,  the 
various  types  of  mental  diseases  are  distinctly  manifest.     The  per- 
ceptions are  bewildered,  there  is  sleeplessness,  loss  of  memory,  de- 
lusion, clouded  reasoning  power,  and  benumbed  moral  sense  follow- 
ing in  the  train  of  alcohol  drinking.     There  is  also  a  monomania 
caused  by  the  prolonged  use  of  alcohol — a  craving  for  drink  that 
knows  no  bounds,  and  but  rarely  a  cure ;  this  is  dipsomania,  or 
thirst-madness.     (Read  Note  14. ) 

64.  The   Impairment  of  the  Will.— The  direct  result  of  the 
taking  of  alcohol  is  seen  in  the  loss  of  self-control.     "  The  worst 
estate  of  man  is  that  wherein  he  loses  the  knowledge  and  govern- 
ment of  himself."     It  is  in  the  formation  of  the  drinking  habit  that 
alcohol  too  often  works  the  absolute  ruin  of  its  devotee,  in  both  body 
and  mind.     It  is  apt  to  be  a  continuous  habit,  having  for  its  sequel 
the  dethronement  of  the  will.     It  may  be  stated,  as  the  rule,  that 
after  forty  years  of  age,  a  man  who  has  formed  this  habit  is  unequal 
by  his  own  strength  of  will  to  abandon  it.     Many  men  of  fine 
intellectual  capacity  and  amiable  qualities  have  become  intemperate, 
and  have  so  continued,  as  long  as  their  efforts  to  get  free  again 
have  not  been  supplemented  by  outside  and  enforced  restraint.* 

14.  Alcohol  a  Poison  of  the  Intellect. — "In  the  normal  state  of  a 
man's  mind,  all  the  faculties,  the  imagination,  the  judgment,  the  memory,  the 
association  of  ideas,  are  regulated  by  another  superior  faculty,  viz. ,  the  atten- 
tion. The  attention  of  the  will  is  the  man  himself ;  it  is  the  ego  which,  being 
in  the  full  possession  of  the  resources  of  which  it  disposes,  takes  them  where 
it  will,  when  it  will,  to  do  whatever  it  pleases.  Now  in  drunkenness,  even  at 
the  very  beginning,  the  will  and  the  attention  have  disappeared.  Nothing  is  left 
but  the  imagination  and  the  memory,  which,  left  to  themselves,  without  regu- 
lation and  without  guides,  produce  the  most  irrational  results. " — Charles  Richet. 

*  "Alcohol  in  small  doses  super-excites  certain  intellectual  faculties — the 
imagination,  the  memory,  and  the  association  of  ideas ;  but  it  paralyzes  others, 
especially  the  will,  the  reflection,  and  judgment.     Yet,  with  a  stronger  dose  all 
trace  of  intelligence  disappears.     When  old  Sly  is  stretched  on  the  ground 
insensible  from  drink  and  snoring  in  the  mud,  he  excites  compassion  and  disgust: 
0  monstrous  beast !  how  like  a  swine  he  lies  ! 
Grim  death,  how  foul  and  loathsome  is  thine  image  ! " 

Charles  Richet,  in  Revue  des  Deux  Mondes. 

63.  What  changes  are  noticed  in  the  mind? 

64.  Give  effect  of  alcohol  upon  the  wilL 


212  THE   NERVOUS   SYSTEM. 

It  is  for  such  as  these  that  inebriate  asylums  have  been  built 
Other  hard  drinkers  drift  into  violence  and  crime,  and  finally  find 
a  curative  restraint  within  prison  walls.  The  benumbing  effects  of 
drinking  habits  upon  the  moral  being  of  man  is  universally  known. 
"All  delicacy,  courtesy,  and  self-respect  are  gone;  the  sense  of 
justice  and  of  right  is  faint  or  quite  extinct ;  there  is  no  vice  into 
which  the  victim  of  drunkenness  does  not  easily  slide,  and  no  crime 
from  which  he  can  be  expected  to  refrain.  Between  this  condition 
and  insanity  there  is  but  a  single  step,"  and  death,  in  a  worldly 
sense  a  deliverance,  in  spite  of  many  an  effort  to  rally,  "  terminates 
the  miserable  scene ;  one  by  one  lights  have  been  removed  from  the 
banquet  of  folly,  and  the  last  is  now  extinguished."  (Read  Note* 
15  andib.) 

65.  An  illustration  of  the  disadvantage  of  drunkenness  to  the 
moral  tone  of  a  community  may  be  drawn  from  the  results  of  the  labors 
of  Father  Matthew,  about  forty  years  ago,  as  a  temperance  reformer. 
In  the  five  years — 1838-1842 — the  consumption  of  whiskey  in  Ire- 
land fell  50  per  cent.;  the  crimes  of  violence  falling  from  64,520  to 

15.  Drunkenness  and  Insanity. — "  The  connection  between  drunken- 
ness  and  crime  and  drunkenness  and  poverty,  is  close  and  unvarying  in  ita 
effect  upon  society.     The  remarkable  increase  of  insanity  in  recent  years  may 
in  part  be  traced  to  the  use  of  intoxicating  beverages.     It  has  been  assertej 
that  at  least  seven-tenths  of  all  the  crime  and  poverty  and  calamity  to  the 
people  of  the  United  States  spring  from  the  abuse  of  liquors." — Dr.  J.  E. 
Reeves. 

16.  The  Effects  of  Mild  Stimulation. — "  Words  of  caution  to  young 
men  concerning  the  injurious  effects  of  tobacco,  as  well  as  indulgence  in  wine 
or  the  pleasures  of  the  table,  elicit,  in  ninety-nine  out  of  one  hundred  cases, 
the  reply,  *It  does  not  hurt  me.'    Does  not  hurt  you  !    Wait  and  see.     In 
years  to  come,  when  you  ought  to  be  in  your  prime,  you  will  be  a  poor, 
nervous,  irritable,  nerve-dried  creature.     Your  hands  will  tremble,  your  head 
will  ache,  your  sleep  be  fitful  and  disturbed,  your  digestion  impaired — in  short, 
the  unnatural  and  transient  pleasure  at  one  end  of  your  life  will  be  more  than 
counterbalanced  by  the  discomfort  and  misery  at  the  other.     It  is  a  truth  of 
the  greatest  moment,  which  ought  to  be  so  impressed  upon  the  mind  as  to  be 
always  rising  up  within  it,  that  transgressions  of  the  laws  of  health,  not  pun- 
ished at  one  end  of  life,  are  sure  to  be  at  the  other." — J.  R  Black  on  the  Ten 
Laws  of  Health. 

45.  Give  results  of  Father  Matthew's  work. 


THE   NERVOUS  SYSTEM.  213 

47,027,  and  executions  from  59  in  the  first  year  to  1  in  the  last 
year.     (Read  Note  17.) 

66.  The  Poisonous  Effects  of  Alcohol. — Alcohol  is,  in  the 
main,  a  narcotic  poison  in  its  effects  upon  human  beings,  although 
the  visible  results  vary  immensely  according  to  the  quantity  taken. 
If  a  sufficient  quantity  is  taken  to  cause  any  visible  result,  a  condi- 
tion known  as  stimulation  is  observed.*  If  an  extremely  large 
dose  is  taken,  a  state  of  stupor  follows,  and  death  has  been  known 
to  result  in  some  cases.  Between  these  two  extremes  there  may  be 
a  variety  of  manifestations.  As  a  stimulant,  it  appears  to  many  to 
have  a  kindly  action,  to  cause  a  glow  and  sense  of  warmth,  to  in- 
crease muscular  activity,  and  to  make  the  mind  and  organs  of  speech 
more  nimble.  Alcohol  is  not  the  only  narcotic  poison  that  exercises 
this  influence,  which  is  not  kindly,  but  is  in  fact  the  first  indica- 

17.  Alcohol  and  Crime. — "  Thirty  years  of  judicial  experience  have 
taught  me  that  of  the  crimes  which  judges  are  called  upon  to  try,  and 
upon  which  sentences  of  the  law  are  pronounced,  more  than  eight-tenths  of 
them  involving  any  degree  of  violence  in  their  character  are  directly  traceable 
to  the  liquor  shops.  How  often  have  I  had  young  men  look  up  at  me  when 
I  asked  them  what  they  had  to  say  why  the  sentence  of  the  law  should  not  be 
pronounced,  declare,  '  I  should  never  have  done  this  crime  if  it  were  not  for 
drink.  Rum  was  my  ruin  ;  rum  struck  the  blow,  and  not  my  hand,  that 
killed  the  man  for  whose  death  I  am  tried ;  rum  has  caused  me  to  beat  my 
wife,  and  injure  my  helpless  child,  and  to  do  the  act  which  now  confines  me  to 
a  prison.' r  — Judge  Noah  Davis. 

*  "Suppose,  for  instance,  you  measure  your  muscular  strength  with  a 
•  health  lift '  or  dynamometer  (by  which  muscular  exertion  can  be  accurately 
measured),  and  then  take  some  of  the  drink,  in  the  strength-inspiring  power 
of  which  you  have  most  confidence,  and  when  you  are  most  exhilarated  by  it, 
and  feel  as  if  you  could  shoulder  a  large  fragment  of  Mount  Olympus,  measure 
your  strength  again.  The  drink  has  fooled  you,  that  is  alL  "You  felt  that  you 
were  stronger  than  natural ;  you  find  that  the  narcotic  has  been  true  to  its 
paralyzing  nature,  and  that  you  are  weaker.  Then,  after  a  time,  when  the 
drug  has  spent  itself,  and  reaction  (so  called)  comes  on,  and  you  feel  weak  and 
prostrated,  measure  your  strength  once  more.  Fooled  again ;  the  stuff  has 
fooled  you  twice.  When  you  felt  yourself  strong  you  were  weak,  and  now  when 
you  feel  yourself  weak,  you  find  yourself  stronger — your  natural  strength  is 
returning,  and  what  you  have  called  reaction  is  in  reality  recovery  from  the 
weakening  effects  of  the  narcotic. n — Dr.  A.  F.  Kinne. 


06.  Poisonous  effects  of  aloonolt 


214  THE   NERVOUS   SYSTEM. 

tion  of  a  paralysis  of  a  portion  of  the  nervous  system.  Most  of  the 
habitual  takers  of  alcohol  freely  admit  that  they  are  injured  by  it 
in  one  way  or  another,  and  still  they  continue  in  their  indulgence. 
In  such  cases  the  mental  balance  is  already  lost ;  for  a  person  to 
covet  that  which  he  knows  to  be  hurtful  to  him,  is  manifestly  not 
the  sign  of  a  sound  mind.  (Read  Note  18.) 

67.  Tobacco  and  its  Effects. — Tobacco,  familiarly  known   as 
"the  weed,"  is  an  annual  plant  said  to  be  a  native  of  America.     It 
grows  to  the  height  of  several  feet,  with  leaves  of  a  pale  green 
color.     These  leaves,  when  dried,  are  made  into  cigars,  chewing- 
tobacco,  and  snuff,  which   are   extensively  used  throughout  the 
civilized  world. 

68.  Tobacco  as  a  Poison. — Tobacco  is  a  poison  to  the  young, 
and  is  far  more  hurtful  to  the  adult  than  is  generally  supposed.     It 
may  be  stated,  as  a  rule,  that  there  are  few  persons  who  use  it 
habitually  that  do  not  suffer  injury  from  it.     The  injury  is  mainly 
caused  by  what  is  known  as  "  nicotine,"  one  of  the  narcotic  poisons, 
and  particularly  prominent  in  tobacco.     Some  of  the  effects  of  its 
limited  use  are  nausea,  vomiting,  vertigo,  and  weakness ;  and  its 
prolonged  use,  by  those  who  are  sensitive  to  it,  often  results  in 
convulsions  and  other  like  symptoms,  together  with  an  irritability 
and  weakened  condition  of  the  heart,  known  to  physicians  as  the 
"tobacco-heart." 

18.  "Here  is  a  company  of  'jolly  good  fellows,'  all  standing  on  their  feet, 
their  faces  red  and  radiant,  and  all  swinging  their  arms  and  talking  at  once. 
These  men  have  been  taking  alcohol,  and,  surely,  you  will  say,  it  has  stimu- 
lated them.  But  if  you  will  attend  for  a  moment  to  what  they  are  saying,  you 
will  see  that  there  is  no  true  brain-stimulation  about  it.  We  shall  be  reminded 
rather  of  what  Addison  says  of  the  difference  between  the  mind  of  the  wise 
man  and  that  of  the  fool :  '  There  are  infinite,  numberless  extravagancies,  and 
a  succession  of  vanities  which  pass  through  both.  The  great  difference  is  that 
the  first  knows  how  to  pick  and  cull  his  thoughts  for  conversation,  by  sup- 
pressing some  and  communicating  others ;  whereas  the  other  lets  them  all 
indifferently  fly  out  in  words.'  The  case  with  these  revelers  is  precisely  this. 
The  poison  which  they  have  taken  has  paralyzed  their  conservative  faculties, 
and  the  talking  propensity  is  running  on  without  anything  to  hold  it  in  check 
and  regulate  it." — Dr.  A.  F.  Kinne. 

67.  Describe  the  tobacco  plant. 

68.  What  is  its  effect  upon  the  nerves? 


THE   NERVOUS   SYSTEM.  215 


69.  Effects  6n  the  Young. — Of  the  pernicious  influence  cf  the 
use  of  tobacco  upon  the  young,  the  testimony  of  the  Naval  and 
Military  Academies  of  the  country  is  very  decided.  It  has  at  times 
been  allowed  in  both  institutions,  but  at  present  it  is  forbidden, 
on  the  ground  that  its  use  is  attended  with  serious  damage  to 
health.  It  is  stated  that  its  prohibition  at  the  Naval  Academy  in 
1881  was  received  with  unanimous  approval  by  the  officers  in 
charge,  and  with  "  great  joy  by  many  of  the  cadets."  Tremor  of 
the  muscles,  caused  by  smoking,  was  very  noticeable  in  the  draw- 
ings that  form  so  important  a  part  of  the  cadets'  work.  A  teacher 
of  drawing,  of  fourteen  years  experience,  has  said  that  he  can 
always  tell  from  the  character  of  the  lines  in  the  drawings,  whether 
or  not  the  pupils  used  tobacco.*  Its  avoidance  has  resulted  in  the 
reduced  number  of  minor  ailments  that  swelled  the  sick-list  in  years 
when  its  use  was  unrestricted.  Athletes  and  other  persons  who 
engage  in  running  matches  and  the  like,  are  commonly  not  allowed 
to  use  either  alcohol  or  tobacco  while  they  are  "in  training;"  their 
use  interferes  with  the  fullest  development  of  muscular  strength. 
(Read  Note  19.) 

*  "Prof.  Mantegazza,  of  Florence,  Italy,  a  distinguished  sanitarian  and  phy- 
sician, testifies  that  '  Tobacco  is  never  necessary ;  it  is  always  hurtful  to  boys 
and  young  men,  to  weak  people,  and  those  disposed  to  consumption.  *  *  *  * 
All  good  citizens  should  try  to  put  a  stop  to  the  general  invasion  of  tobacco, 
which  threatens  to  involve  the  whole  of  Europe  in  a  dense  cloud  of  smoke, 
which  poisons  even  those  who  do  not  smoke.'" 

19.  "The  end  of  all  science  is  to  secure  long  life  and  good  health  to  the 
individual  and  the  race,  and  it  ought  to  be  a  part  of  the  rational  creed  of  every 
good  man  and  woman  to  abjure  the  use  of  tobacco,  and  keep  others  from  fall- 
ing into  the  vice." — Dr.  C.  E.  Drysdale. 

"Of  tobacco,  Franklin  said  that  he  could  not  think  it  had  ever  done  much 
good  in  the  world,  since  he  never  knew  a  person  who  used  it  habitually  wht 
would  recommend  another  to  do  the  same." 

"Tobacco  is  certainly  not  a  food  for  man,  nor  has  it  much  value  as  a  medicine 
The  tobacco- worm  is  the  only  animal  known  to  thrive  upon  it." — F.  H.  Hamilton. 

"  An  illustration  of  the  depressing  influence  of  tobacco  is  given  by  Dr.  Jacob 
Bigelow,  who  states  that  soldiers,  when  wishing  to  shirk  duty  and  get  on  the 
sick-list,  sometimes  succeed  in  bringing  on  the  symptoms  of  alarming  sickness 
by  wearing  a  piece  of  tobacco  under  each  arm-pit.  The  skin  absorbs  sufficient 
of  the  poison  to  affect  the  system  to  a  marked  degree." 

(30.  Gire  the  effect*  of  tobacco  upon  the  young  1 


216  THE   NERVOUS   SYSTEM. 

70.  Cigarette-Smoking. — This  form  of  taking  tobacco  is  inju- 
rious in  two  particulars  that  do  not  apply  to  the  other   forma 
The  smoker  of  cigarettes,  either  voluntarily  or  involuntarily,  takes 
into  his  lungs  a  very  large  amount  of  smoke,  and  with  it  that 
hurtful   element,  carbonic   oxide.     Again,   there   is  an   excessive 
amount  of  adulteration  of  the  tobacco  in  cigarettes;  and  one  sub- 
stance, opium,  is  largely  so  used  and  is  extremely  injurious. 

71.  Snuff- Taking.— In  addition  to   the  hurtful  effects  of  tobacco 
generally,  snuff-taking  is  notoriously  injurious  to  the  senses  of  smell 
and  taste,  and  to  the  voice. 

72.  Narcotics. — The  term  narcotic  is  applied  to  different  sub- 
stances derived  chiefly  from  the  vegetable  kingdom,  which  have 
the  wonderful  property  of  quieting  pain  and  causing  sleep.     .Next 
in  importance  to  alcohol,  which  belongs  to  the  narcotics,  are  opium 
(and  its  preparations),  chloral  hydrate,  hasheesh  and  chloroform. 

73.  Opium. — Opium  is  the  thickened  juice  of  the  poppy-plant 
of  India,  and  is  commonly  regarded  as  the  most  important  of  the 
narcotics.     Its  active  principle  is  morphine,  which  gives  the  sooth- 
ing property  to  laudanum,  paregoric,  and  Dover's  powders.     It  is 
also  used  in  nostrums  to  put  infants  to  sleep :  but  unwisely  used, 
often  brings  on  a  sleep  that  knows  no  waking. 

74.  Effects    of   Opium.  —  Opium   is   particularly   injurious  to 
the  young,  even  small  doses  sometimes  producing  alarming  symp- 
toms.    Upon  adults  the  external  effects  are  not  as  noticeable  as  are 
those  of  alcohol,  but  the  mind  is  more  deeply  stirred  and  the  flow  of 
ideas  more  copious. 

75.  Danger  from  Opiates. — The  use  of  opium  for  relieving 
pain   has   been   known  for  hundreds   of  years.     The   enchanting 
sense  of  relief  to  suffering  wrought  by  opiates  leads  to  the  mor- 
phine habit,  commonly  called  opium-eating.     It  will  be  seen,  there- 
fore, why  such  great  care  is  exercised  by  physicians  in  administering 
opiates,  lest  their  patients  afterward  fall  into  the  habit  of  taking 
them  without  medical  advice.    (Read  Note  20. ) 

20.  "  The  opium-eater  loses  none  of  his  moral  sensibilities  or  aspirations ; 
he  wishes  and  longs  as  earnestly  as  ever  to  realize  what  he  believes  possible, 

70.  What  is  said  of  cigarette-smoking  ?  73.  What  is  opium? 

71.  Snuff-taking?  74.  What  are  the  effects  of  using  opium  ? 

72.  What  do  you  understand  by  narcotics  ?    75.  What  the  danger? 


THE    NERVOUS   SYSTEM.  217 

76.  Physiological    Effects  of  Opium. — The    frequent  use  of 
opium   disturbs  and  weakens  the  stomach   as   well   as  the   other 
digestive  organs ;  hence  we  invariably  find  the  opium-eater  to  be 
a  lean,  yellow,  sallow  person.      His  muscular  and  mental  powers 
are  impaired,  and  his  will  is  terribly  enfeebled.     This   dreadful 
habit  can  be  broken  only  with  unspeakable  suffering  to  its  victim. 

77.  Chloral    Hydrate.  —  Chloral    hydrate,    commonly    called 
chloral,   is    produced   from   alcohol;  but  its  power  as  a  sedative 
was   not    generally  known  until   within    the    past   twenty   years. 
It  also  is  a  destroyer  of  appetite  as  well  as  of  digestion,  unless 
.prescribed  in  proper  doses,  and  the  unfortunates  once  given  over 
to  it  find  themselves  unable  to  sleep  without  its  continued  use. 
It  should  never  be  taken  except  under  the  direction  of  a  physician. 

78.  Hasheesh. — Hasheesh,  the  juice  of  Indian  hemp,  is  said  to 
be  used  by  millions  of  tl&  inhabitants  of  Asia.     It  is  not  much 
known  in  the  western  countries.    In  the  East  the  excitement  caused 
by  its  use  takes  the  form  of  furious  madness,  leading  its  victim  to 
commit  acts  of  violence  and  murder.    Hence  the  term  "  hasheeshers  " 
in  our  language  has  come  to  be  synonymous  with  assassins.    (Read 
Note  21.) 

79.  Chloroform. — Chloroform,  another  product  from  alcohol,  is 

and  feels  to  be  exacted  by  duty ;  but  his  intellectual  apprehensions  of  what  is 
possible  infinitely  outruns  his  power,  not  of  execution  only,  but  even  the  power 
to  attempt.  He  lies  under  the  weight  of  incubus  and  nightmare ;  he  lies  in 
sight  of  all  that  he  would  fain  perform,  just  as  a  man  forcibly  confined  to  his 
bed  by  the  mortal  languor  of  a  relaxing  disease,  who  is  compelled  to  witness 
injury  and  outrage  offered  to  some  object  of  his  tenderest  love ;  he  curses  the 
spells  which  chain  him  down  from  motion;  he- would  lay  down  his  life  if  he 
might  but  get  up  and  walk ;  but  he  is  powerless  as  an  infant,  and  cannot  even 
attempt  to  rise. " — De  Quincey's  Confessions  of  an  Opium-Eater. 

21.  "As  everybody  knows,  the  intoxication  caused  by  alcoholic  liquors,  by 
hasheesh,  by  opium,  after  a  first  period  of  excitement,  brings  about  a  notable 
impairment  of  the  will.  The  individual  is  more  or  less  conscious  of  this; 
other  persons  see  it  more  clearly.  Soon— especially  under  the  influence  of 
alcohol — the  weakening  of  the  will  becomes  excessive.  The  extravagances, 
violences,  and  crimes  committed  in  this  state  are  innumerable." — Dr.  T.  Kiboi, 


76.  What  affect  upon  the  system  ? 

77.  What  do  you  know  of  chloral  hydrate  1 

78.  What  is  hasheesh  ?    Its  use  ? 

79.  Chloroform?    Its  use  I 


10 


218  THE    NERVOUS    SYSTEM. 

used  by  inhalation  when  surgical  operations  are  to  be  performed. 
As  it  is  very  powerful  and  subtle  in  its  action,  the  unskillful  use 
of  it  is  dangerous  in  the  extreme.  The  habit  of  taking  chloroform 
by  those  who  are  great  physical  sufferers,  or  whose  constitutions 
have  been  wrecked  by  the  use  of  other  narcotics,  should  be  dis- 
couraged. It  too  often  happens  that  the  career  of  such  is  short. 
for  the  drug  may  easily  be  taken  in  excess  and  so  cause  death. 

80.  Sleep  Produced  by  Narcotics. — Opium  and  the  opiates 
have  the  power  of  quieting  the  activity  of  the  brain,  and  of  com- 
pelling sleep.     This  may'  be  a  blessed  action  if  skilfully  applied 
by  the  physician,  but  not  so  applied  it  is  the  source  of  infinite  peril 
The  sleep  so  caused  differs  from  natural,  restful  slumber,  especially 
in   the    fact  that  the  after  effects  are  commonly  depressing  and 
disturbing  to  the  brain  to  the  extenLof  being   harder   to   beai 
than  the  wakefulness  on  account  of  wjich  the  drugs  are  taken. 
Very  young   persons   arV  especially   subject   to   injury  by  sleep- 
producing  medicines ;   and  many  are  the  deaths  that  have  been 
caused  among  infants  by  the  giving  of  "  soothing  syrups,"  "  cordials," 
and  "anodynes,"  that  are  so  freely  made^nd  sold  for  the  purpose  of 
compelling  sleep. 

81.  Results  of  the  Use  of  Narcotics. — The  use  of  any  of  these 
narcotics,  without  proper  medical  advice,  is  their  abuse.     In  this 
way  they  become  powerful  for  harm.    They  are  no  longer  remedies, 
but  poisons.     Self-prescribed,  they  have  a  thousand  times  been  the 
instrument  of  unintentional  suicide.  .  (Read  Note  22. ) 

22.  The  Narcotics  and  Digestion. — "The  habitual  use  of  opium  and 
other  narcotic  drugs  is  unfriendly  to  digestion,  leading  to  nausea  and  a 
distaste  for  wholesome  food.  The  vigor  of  the  organs  of  digestion  is 
impaired. 

"  The  disturbing  effects  of  tobacco,  in  producing  nausea  and  vomiting,  Is 
well  known,  and  is  almost  the  invariable  experience  of  all  beginners  in  the  use 
of  that  substance ;  loss  of  appetite  is  a  very  frequent  result  of  the  habitual 
use  of  it"  

80.  What  kind  of  sleep  produced  by  narcotics? 

81.  What  the  results  of  the  use  of  narcotics  ? 


THE    NBEVOU-    SYSTEM. 


QUESTIONS    FOR    TOPICAL    REVIEW. 

PAQB 

L  State  fully  what  is  meant  by  the  terra  vegetable  function 181 

2.  To  what  does  man  owe  his  position  as  the  head  of  the  animal  creation  ?. 182 

3.  What  can  you  state  on  the  subject  of  special  organs  for  separate  functions  ?. 182 

4.  Describe,  as  fully  as  you  can,  the  structure  of  the  nervous  system ,    182,  183 

5.  Describe  the  brain,  its  location,  size,  shape,  and  structure 183 

6.  Describe  the  brain  proper,  or  cerebrum 185 

7.  Describe  the  little  brain,  or  cerebellum 187 

8.  Describe  the  spinal  cord  ...* 188 

9.  What  are  the  spinal  nerves,  $nd  how  are  they  arranged  ? 189 

10.  What  is  the  character  and  substance  of  their  tissues  TK 189 

11.  State  and  illustrate  how  the  nerve-fibres  perform  their  office 190 

12.  Describe  the  sympathetic  system  of  nerves 190, 191 

13.  State  the  properties  of  nervous  tissue,  and  illustrate 192 

14.  Explain  the  functions  of  the  nerves 194 

What  is  meant  by  transient  paralysis  of  a  nerve  ?    Illustrate 195 

•""16.  What  can  you  state  of  the  me  of  me'ssage-motion  along  a  nerve  ? 196 

17.  What  are  the  functions  of  the  spJB^eord? 196 

18.  State  what  you  can  of  the  form  W  paralysis  known~as  paraplegia 196 

19.  What  experiments,  with  results,  upon  the  spinal  cord  are  noted  ?. 197 

20.  Give  the  direction  of  fibres  of  cord » 197 

21.  How  does  the  left  side  of  brain  feel  pain  in  right  hand? 198 

22.  What  is  understood  by  the  reflex  action  of  the  cord? 198 

23.  What  experiments  are  mentioned  to  prove  this  power  of  the  cord  ? 198 

24.  What  are  the  uses  of  the  reflex  action  of  the  cord? 200 

25.  What  is  the  medulla  oblongata  and  its  function? 203 

26.  What  can  you  state  of  the  functions  of  the  cranial  ganglia  ? 204 

27.  What  are  the  functions  of  the  cerebellum? 204 

2S.  What  is  the  i'unc.tinn  of  the  ccrelirum  ? 204 

20.  In  \v3iat  vvay  -Ices  the  su-.e  of  the  linun  generally  indicate  the  character? 205 

80.  What  facts  show  that  the  gray  substance  of  the  brain  is  insensitive  ? 206 

81.  Upon  what  does  the  faculty  of  language  seem  to  depend  ? 207 

82.  Of  what  importance  is  the  reflex  action  of  the  brain?.... 208 

83.  In  what  ways  is  this  importance  made  manifest? 209 

34.  Givti  the  effects  of  alcohol  upon  the  brain  ....^. 210 

85.  How  does  it  affect  the  mind? ; 211 

36.  What  is  said  of  the  effect  upon  the  will? .*. 211 

37.  How  is  the  whole  system  affected  ?. 218 

88.  What  is  aaid  of  tobacco? 214 

89.  Define  and  illustrate  the  term  narcotic 216 

40.  Give  the  statement  regarding  opium .  ...  216 

41.  State  what  you  can  of  chloral 217 

42.  What  is  hasheesh  and  its  effect? 217 

43.  What  is  said  of  chloroform? 218 

44.  Give  general  results  of  use  of  narcotics. ~  ............. 218 


THE  SPECIAL  SENSES. 

The  Production  of  Sensations—  Variety  of  Sensations— General  Sensibility—Pain 
and  its  Function — Special  Sensation,  Touch,  Taste,  Smell,  Sight,  and 
Hearing — The  Hand,  the  Organ  of  Touch— The  Sense  of  Touch — Delicacy 
of  Touch — Sensation  of  Temperature  and  Weight — The  Tongue,  the  Organ 
of  Taste — The  Nerves  of  Taste — The  Sense  of  Taste  and  its  lielations  with 
the  other  Senses — The  Influence  of  Education  on  the  Taste — The  Nasal 
Cavities,  or  the  Organs  of  Smell — The  Olfactory  Nerve — The  Uses  of  the 
Sense  of  Smell — The  Sense  of  Sight — Light — The  Optic  Nerve— The  Eye- 
ball and  Us  Coverings — The  Function  of  the  Iris — The  Sclerotic,  Choroid, 
and  Retina — The  Tears  and  their  Function — The  Movements  of  the  Eye- 
ball—  The  Function  of  Accommodation — TM  Sense  of  Hearing  and, 
Sound — The  Ear,  or  the  Organ  of  Hearing — The  External,  Middle,  and 
Internal  Ear. 

1.  Production  of  Sensations. — We  have  already  seen  that  the 
true  centre  of  sensation  is  some  organ  within  the  skull,  probably 
among  the  gray  masses  at  the  base  of  the  brain ;  but  the  mind  never 
perceives  impressions  at  that  point;  on  the  contrary,  it  always  refers 
them  to  the  external  organs  of  sensation.     Hence,  it  is  convenient 
to  say  that  those  outer  parts  possess  the  property  of  sensibility. 
For  instance,  we  say  that  we  hear  with  the  ear,  taste  with  the 
tongue,  and  feel  with  the  fingers.     That  this  is  not  the  exact  truth 
is  proved  by  the  fact  that,  whenever  the  nerve  connecting  one  of 
these  organs  with  the  brain  is  severed,  it  at  once  loses  its  capacity 
for  sensation. 

2.  Consciousness,  another  faculty  of  the  brain,  is  necessary  to 
complete  a  sensation.      During   sleep,  and   in   other  unconscious 
states,  the  usual  impressions  are  presented  to  the  ear,  the  nose,  and 


1.  True  centre  of  sensation  ?    Place  of  the  mind's  impressions  ?    What  is  it  convenient  to 
•ay?    What  further  is  stated ? 

2.  Consciousness?    During  sleep?    In  profound  insensibility  ? 


THE   SPECIAL  SENSES.  221 

the  skin;  but  they  fail  to  excite  sensations,  because  the  nerve-centres 
are  inactive.  In  profound  insensibility,  from  chloroform  or  ether,  a 
limb  may  be  removed  without  occasioning  the  least  feeling. 

3.  Variety  of  Sensations. — All  animals  have  some  degree  of 
sensibility.      It  is,   of  course,  feeble  and  indistinct   in  the  lower 
forms  of  life,  but  increases  in  power  and  variety  as  we  ascend  the 
scale.      In  the  earth-worm,  the  nervous  system  is  very  simple,  the 
sensibility  being  moderate  and  alike  in  all  parts ;  hence,  if  its  body 
be  cut  into  two  pieces,  each  piece  will  have  the  same  degree  of  feel- 
ing   as  before.     As   we   approach   man,    however,   the   sensations 
multiply  and  become  more  acute ;  the  organs  are  more  complex,  and 
special  parts  are  endowed  with  special  gifts.      These  special  organs 
cannot  be  separated  from  the  rest  of  the  body  without  the  loss  of 
the  functions  they  are  designed  to  exercise. 

4.  The  lowest  form  of  sensation — that  of  simple  contact — is  pos- 
sessed by  the  lowest  of  the  animal  creation.     The  highest  forms  are 
those  by  which  we  are  enabled  to  know  the  properties  of  external 
objects,  such  as  shape,  size,  sound,  and  color.      A  variety  of  means 
of  communicating  with  the  outer  world  is  the  necessary  possession 
of  a  high  intelligence.     Sensations  are  modified   by   use.     They 
become  more  acute  and  powerful  by  moderate  exercise,  or  they  are 
dulled  by  undue  excitement.     The  former  is  shown  by  the  acute 
hearing  of  the  Indian,  by  the  sharp  sight  of  the  sailor,  and  by  the 
delicate   touch   of   the   blind.     The   latter   is   exemplified  by  the 
impaired  hearing  of  the  boiler-maker,  and  the  depraved  taste  of  him 

M  who  uses  pungent  condiments  with  his  food.  Again,  impressions 
habitually  presented  may  not  be  consciously  felt,  as  is  the  case  with 
the  rumbling  of  carriages  in  a  neighboring  street,  or  the  regular 
ticking  of  a  clock.  All  sensations  become  less  vivid  with  the 
advance  of  age,  especially  hearing  and  vision. 

5.  General  Sensibility. — There  is  a  property  possessed  by  nearly 
all  parts  of  the  human  body  which  we  call  genera]  sensibility.    We 
have  recently  seen  that  the  brain  is  wholly  insensitive,  and  may  be 
cut  or  pinched  without  pain.     The  same  is  true  of  the  nails,  hair, 

3.  Sensibility  in  animals?    Tn  the  earth-worm?    In  man? 

4.  The  lowest  form  of  sensation  ?  The  highest?   Sensations,  how  modified  ?  What  further 
can  you  state  as  to  habitual  impressions  r 

5.  G-neral   sensibility?    What  have  we  seen  as  regards    the    brain?    Of  what  other 
structures  is  the  same  true  ? 


222  THE   SPECIAL   SENSES. 

the  scarf-skin  or  external  covering  of  the  body,  and  a  few  other 
structures.  In  these  parts  no  nerves  are  found.  On  the  other 
hand,  the  sensibility  of  the  true  skin,  and  of  mucous  membranes,  as 
of  the  eye  and  nose,  is  exquisite,  these  organs  having  a  large  supply 
of  sensory  nerve-fibres.  The  bones  and  tendons  have  less  of  these 
fibres,  and  are  only  moderately  sensitive. 

6.  The  sensibility  of  any  part  of  the  body,  then,  depends  upon 
the  number  of  nerves  present ;  and,  as  a  rule,  the  nervous  supply  is 
proportional  to  the  importance  of  the  part,  and  to  its  liability  to 
injury.     When,  therefore,  a  surgical  operation  is  performed,  the 
most  painful  part  of  it  is  the  incision  through  the  skin — the  mus- 
cles,  cartilage,  and  bone  being   comparatively  without  sensation. 
Hence,  if  we  could  benumb  the  surface,  certain  of  the  lesser  opera- 
tions might  be  undergone  without  great  inconvenience.     This  is,  in 
fact,  very  successfully  accomplished  by  means  of  the  cold  produced 
by  throwing  a  spray  of  ether,  or  of  some  other  rapidly  evaporating 
liquid  upon  the  part  to  be  cut. 

7.  Tickling  is  a  modification  of  general  sensibility.     At  first  it 
excites  a  pleasurable  sensation,  but  this  soon  passes  into  pain.     It 
is  only  present  in  those  parts  where  the  sense  of  touch  is  feeble. 
But  all  impressions  are  not  received  from  without ;  there  are,  also, 
certain  internal  sensations,  as  they  are  called,  which  depend  upon 
the  condition  of  the  internal  organs,   such   as   appetite,  hunger, 
thirst,    dizziness   when   looking   down   from   some   lofty  position, 
drowsiness,  fatigue,  and  other  feelings  of  comfort  or  discomfort. 
General  sensibility,  whether  of  the  internal  or  external  organs  of 
the  body,  chiefly  depends  upon  the  sensory  fibres  of  the  spinal 
nerve.     The   face,    however,    is   supplied   by   the   sensory  cranial 
nerves.     The  sympathetic  system  has  a  low  grade  of  feeling  in 
health,  but  disease  in  the  parts  served   by  it  arouses  an  intense 
degree  of  pain. 

8.  The  Sensation  of  Pain. — What  then  is  pain?    Is  it  iden- 
tical with  ordinary  sensibility]     There  seems  to  be  some  necessary 
connection  between  the  two  feelings,  for  they  take  place  through 

6.  The  cause  of  sensibility?     Painful  part  in  a  surgical  operation?     Benumbing  the 
surface  ?    How  done  by  ether? 

7    Tickling*    Internal  sensations?    The  nerves  of  general  sensibility? 
8.  Connection  between  pain  and  sensibility? 


THE    SPECIAL    SENSES.  223 

the  same  channels,  and  they  are  alike  intense  in  the  same  situ- 
ations. But  sensibility  habitually  contributes  to  our  sources  of 
pleasure — the  very  opposite  of  pain ;  hence,  these  feelings  cannot  be 
identical. 

9.  Pain  must,  therefore,  be  a  modification  of  the  general  sensi- 
bility which  follows  an  excessive  degree  of  excitement  of  the 
nerves,  there  being  a  natural  limit  to  the  amount  of  stimulation 
which  they  will  sustain.  So  long  as  this  limit  is  observed,  the 
part  excited  may  be  said  to  be  simply  sensitive;  but  when  it  is 
exceeded,  the  impression  becomes  painful.  This  difference  between 
sensibility  and  pain  is  well  shown  by  the  effects  of  sunlight  upon 
the  eye.  The  indirect  illumination  of  the  sun  arouses  only  the 
former  feeling,  and  is  indispensable  to  our  comfort  and  existence, 
while  the  .direct  ray  received  into  the  eye  occasions  great  pain. 
,  rT  10.  The  Uses  of  Pain. — The  dread  of  pain  is  a  valuable  moni- 
x  tor  to  the  body.  It  puts  us  on  our  guard  in  the  presence  of  danger, 
teaches  moderation  in  the  use  of  our  powers,  indicates  the  approach 
of  disease,  and  calls  attention  to  it  when  present.  The  word  dis- 
ease, in  fact,  according  to  its  original  use,  had  reference  simply  to 
the  pain,  or  want  of  ease,  which  commonly  attends  disordered 
health.  When  we  observe  the  serious  mishaps  which  occur  when 
sensibility  and  pain  are  absent,  we  cannot  fail  to  appreciate  its 
value.  For  example,  a  paralytic,  in  taking  a  foot-bath,  forgets  to 
test  its  temperature,  and  putting  his  limbs  into  water  while  it  is  too 
hot,  is  severely  scalded  without  knowing  it. 

11.  A  traveler,  overcome  by  cold  and  fatigue,  lies  down  and  falls 
asleep  near  a  large  fire,  and  when  he  is  aroused  in  the  morning,  it 
is  discovered  that  one  of  his  feet  has  been  .insensibly  destroyed.     A 
grain  of  sand,  lodging  in  an  insensitive  eye,  may  cause  inflamma- 
tion, and  even  the  loss  of  sight.     If  intense  light  were  not  painful 
to  the  eye,  many  a  child  would  innocently  gaze  upon  the  glories  of 
the  sun  to  the  ruin  of  his  sight. 

12.  Pain  is,  indeed,  a  present  evil,  but  its  relations  with  the 
future  prove  its  mission  merciful.     Painful  impressions  cannot  be 

9.  Explain  the  difference  between  pain  and  sensibility. 

10.  Dread  of  pain  ?    How  may  its  value  be  appreciated  ?    Example  ? 

11.  The  case  of  the  traveler?    Grain  of  sand  ?    The  sun  and  child? 

12.  Miwion  of  pom  t    Painful  impressions  compared  with  those  of  pleasure  ? 


224  THE   SPECIAL   SENSEa 

recollected  from  past  experience,  and  they  cannot  be  called  into 
existence  by  the  fancy.  Considered  in  the  light  of  results,  pain 
has  a  use  above  that  of  pleasure ;  for,  while  the  immoderate  pursuit 
of  the  latter  leads  to  harm,  the  tendency  of  pain  is  to  restrict  the 
hurtful  courses  of  life,  and  in  this  manner  to  protect  the  body. 

13.  The  relations  of  pain  to  pleasure  are  thus  described  by  the 
eminent  physiologist,  Magendie : — "By  these    sensations    Nature 
induces  us  to  concur  in  the  order  which  she  has  established  among 
organized  beings.     Though  it  may  appear  like  sophistry  to  say  that 
pain  is  the  shadow  of  pleasure,  yet  it  is  certain  that  those  who  have 
exhausted  the  ordinary  sources  of  pleasure  have  recourse  to  the 
causes  of  pain,  and  gratify  themselves  by  their  effects.     Do  we  not 
see  in  all  large  cities,  that  men  who  are  debauched  and  depraved 
find  agreeable  sensations  where  others  experience  only  intolerable 
pain?"    (Read Note  \.} 

14.  As  to  painful  sensation  among  the  inferior  animals,  the  plan 
of  Nature  seems  to  be,  that  the  higher  the  intelligence  of  the  crea- 

1.  Pain  is  "Nature's  Harbinger  of  Mischief'— " It  must,  there- 
fore, be  evident  that  pain  is,  under  certain  circumstances,  really  beneficial.  It 
is  often  a  great  boon  to  have  a  sensitive  stomach ;  for  those  who  suffer  pain 
after  food  are  less  apt  habitually  to  err  in  diet,  and  urns  to  become  dyspeptic 
or  gouty,  than  those  whose  organs  receive  everything  uncomplainingly.  Pain 
in  the  stomach  is  frequently  due  (in  well-to-do  people)  to  the  fact  that  they 
won't  work  and  will  eat ;  not  that  the  stomach  itself  is  weak  (as  they  think), 
but  that  the  supply  of  food  being  greater  than  the  demand,  the  system  becomes 
overstocked.  In  dyspepsia  the  cause  is  very  often  far  away,  and  the  stomach 
is  no  more  the  cause  of  the  malady  than  the  big  toe  is  of  the  gout ;  but  if  the 
stomach  gave  no  signs  of  perturbation,  the  evil  would  be  allowed  longer  to 
exist  unnoticed.  We  should  always  give  early  attention  to  pain,  and  discover 
its  causes  before  they  become  too  complex  to  be  unraveled,  and  before  the 
derangement  which  its  presence  indicates  becomes  permanent.  The  follow- 
ing incident  well  illustrates  the  extent  to  which  pain  may  be  dependent  on 
fancy:  *  A  butcher  was  brought  into  a  druggist's  from  the  market-place  oppo- 
site, laboring  under  a  terrible  accident.  The  man,  on  trying  to  hook  up  a 
heavy  piece  of  meat  above  his  head,  slipped,  and  the  sharp  hook  penetrated 
his  arm  so  that  he  himself  was  suspended.  On  being  examined,  he  was  pale, 
almost  pulseless,  and  expressed  himself  as  suffering  acute  agony.  The  arm 
could  not  be  moved  without  causing  excessive  pain,  and  in  cutting  off  the 

13.  What  does  Magendie  say  of  the  relation  of  pain  to  pleasure? 

14.  The  law  of  Nature  as  regards  painful  sensations  among  animals  t 


THE   SPECIAL  SENSES,  225 

fcure,  and  the  more  complete  its  power  of  defence,  the  more  acute  is 
its  sensibility.  We  infer,  therefore,  that  animals  low  in  the  scale 
of  existence,  and  helpless,  are  not  very  liable  to  suffer  pain. 

15.  Special  Sensation. — The  sensations  of  simple  contact  and 
pain  are  felt  by  nearly  all  parts  of  the  system,  whether  external 
or  internal,  and  are  the  necessary  consequence  of  the  general 
sensibility;  but,  so  far  as  the  objects  which  surround  us  are  con 
cerned,  these  impressions  are  vague  and  passive  in  character,  and 
inform  the  mind  of  none  of  the  properties  or  powers  of  these 
objects.  Besides  these  feelings,  therefore,  man  is  endowed  with 
certain  special  sensations,  which  are  positive  and  distinct  in  charac- 
ter, and  which  he  can  call  into  exercise  at  will,  and  employ  in 
the  pursuit  of  knowledge.  For  reasons  relating  to  the  original 
constitution  of  the  body,  these  sensations  are  to  be  regarded  as 
modifications  of  the  general  sensibility  already  alluded  to,  con- 
structed with  special  reference  to  the  different  forces  of  Nature  of 
which  we  have  any  knowledge,  such  as  heat,  motion,  gravity,  sun- 
light, and  the  lika  (Read  Note  2.) 

sleeve  he  frequently  cried  out ;  yet,  when  the  arm  was  exposed,  it  was  found 
quite  uninjured,  the  hook  having  only  traversed  the  sleeve  of  the  coat!1  The 
sensation  here  was  perfectly  real,  but  originated  in  a  change  of  the  brain  and 
nerves,  instead  of  in  the  external  senses." — Notes  on  Pain. 

2.  The  Mutual  Relations  of  the  Special  Senses. — "  A  blind  man 
attempting  to  express  his  notion  of  scarlet,  said  it  resembled  the  sound 
of  a  trumpet.  We  are  constantly  reminded  of  the  impressions  of  one 
sense  by  the  operations  of  another.  To  my  ear  the  bass  note  in  music 
is  what  a  dull  black  is  to  the  eye.  The  reverberations  of  deep  thunder  seem 
like  boulders  with  worn  angles — with  profiles  blunt  and  irregular,  as  if  drawn 
by  the  jerking  pencil  of  the  lightning ;  and  one  who  never  had  the  pleasure  oJ 
seeing  stars  from  a  blow  on  the  head,  may  get  a  tolerably  correct  idea  of  that 
kind  of  galaxy  by  snuffing  at  a  bottle  of  volatile  salts. 

"  Language  is  full  of  effort  to  report  the  impressions  of  one  sense  by  the 
symbols  of  another.  We  say  that  an  apple  is  sweet,  that  a  rose  is  sweet,  a 
face  is  sweet,  a  strain  of  music  is  sweet,  and  love  is  sweet,  not  to  mention  the 
saccharine  reaction  of  the  'uses  of  adversity.'  Here  taste,  smell,  sight,  hear- 
ing, and  a  social  sentiment  use  the  same  word  for  that  pleasurable  sensation 
experienced  by  the  mind  through  each  distinctive  organ.  We  assist  the  organ 
of  one  sense  by  that  of  another.  We  open  the  lips  and  part  the  teeth  a  little 

15.  The  sensation  of  contact  and  pain  t    Special  sensation*  of  man  f    How  regarded! 


THE    SPECIAL   SENSES. 

16.  These  distinct  and  active  faculties  are  termed  the  special 
senses,  and  are  five  in  number,  viz.,  Touch,  Taste,  Smell,  Sight,  and 
Hearing.     For  the  exercise  of  these  senses,  special  organs  are  fur- 
nished, such  as  the  hand,  the  tongue,  the  nose,  the  eye,  and  the 
ear.     The  manner  in  which  the  nerves  of  special  sense  terminate 
varies  in  the  case  of  each  organ,  so  that  each  is  adapted  to  one  set 
of  sensations  alone,  and  is  incapable  of  perceiving  any  other.     Thus 
the  nerve  of  hearing  is  excited  by  the  waves  of  sound,  and  not  by 
those  of  light,  while  the  reverse  is  true  of  the  nerve  of  sight;  and 
the  nerve  of  smell  can  appreciate  neither  of  them,  being  capable 
only  of  taking  cognizance  of  the  odorous  properties  of  bodies. 
(Read  Note  3.) 

17.  By  some  writers  six  senses  are  accorded  to  man,  the  addi- 

when  we  are  eager  to  hear ;  we  listen  and  turn  the  eyes'  attention  inward  when 
we  would  detect  a  delicate  taste,  or  remember  a  faded  impression. 

"  But  this  mutual  accommodation  of  the  senses  is  not  so  marvelous  as  it 
may  seem,  when  we  remember  that  the  whole  five,  six,  or  seven,  as  you  please, 
are  but  one  power  of  nervous  perception,  specialized  into  a  variety  of  functions, 
differentiated,  as  the  learned  say,  that  we  may  have  more  perfect  work  by  a 
division  of  labor.  The  same  necessity  which  developed  nerve-contact  into 
sight  on  the  one  hand  and  hearing  on  the  other,  might  also  express  through 
one  of  these  the  sensations  proper  to  the  other,  when  the  other  was  wanting. 
Seal  up  the  eyes  of  a  bat,  say  the  naturalists,  and  let  it  loose  in  a  room  crossed 
with  wires  in  every  direction,  and  he  will  fly  clear  of  them  all,  as  if  he  had 
other  means  of  perception  as  sensitive  as  the  optic  nerve. 

"  Laura  Bridgman,  with  neither  sight,  hearing,  nor  smell,  could  detect  the 
presence  of  a  stranger  in  the  room,  without  contact  Her  mind  then  must 
have  as  distinct  an  image  of  every  person  as  we  have,  yet  not  one  of  what  we 
call  our  senses  could  go  to  the  making  up  of  that  image.  It  could  not  be  form 
as  we  know  it,  nor  a  voice,  nor  an  odor,  but  it  was  itself  other  than  all,  excit- 
ing emotions  of  love,  or  hate,  gratitude  or  repugnance,  and  the  thought  it 
excited  must  have  had  shape,  though  it  is  not  easy  to  imagine  how." — Tlw 
Schoolmaster. 

3.  Variation  in  Structure  in  the  Nerves  of  Special  Sense.— 
"While  in  the  more  intellectual  senses — Sight,  Hearing,  and  Touch — the 
nerves  have  their  protecting  and  isolating  sheaths  corresponding  with  the  dis- 
tinctness and  separateness  of  the  parts  of  the  impression,  in  Smell,  the  nervea 
are  a  plexus  of  unsheathed  fibres,  corresponding  with  the  fusion  of  the  odorous 
impression  into  one  whole,  without  distinction  of  parts." — Herbert  Spencer. 

16,  What  are  the  special  senses?    Special  organs  for  them  T          * 

17.  What  is  said  in  relation  to  one  more  than  the  five  senses  I 


THB   SPECIAL  SENSES.  227 

fcional  ore  being?  either  the  sense  of  temperature — for,  as  we  shall 
presently  see,  this  is  not  the  same  as  touch — or.  according  to  others, 
the  muscular  sense  by  which  we  are  enabled  to  estimate  the  weights 
of  bodies.  The  latter  also  differs  in  some  respects  from  the  sense 
of  touch. 

18.  Organs  of  Touch. — The  sense  of  touch  is  possessed  by 
Dearly  all  portions  of  the  general  surface  of  the  body,  but  it  finds 
its  highest  development  in  the  hands.  The  human  hand  is  prop- 
erly regarded  as  the  model  organ  of  touch.  The  minute  structure 
of  the  skin  fits  it  admirably  for  this  form  of  sensation ;  the  cuticle, 
or  scarf-skin,  is  fine  and  flexible,  while  the  cutis,  or  true-skin,  con- 
tains multitudes  of  nerve-filaments,  arranged  in  rows  of  papillce  or 
cone-like  projections,  about  one  one-hundredth  of  an  inch  in  length. 
It  is  estimated  that  there  are  20,000  of  these  papillae  in  a  square-inch 
of  the  palmar  surface  of  the  hand.  Now,  although  the  nerves  of 
the  cutis  are  the  instruments  by  which  impressions  are  received  and 
transmitted  to  the  brain,  yet  the  cuticle  is  essential  to  the  sensation 
of  touch.  This  is  shown  by  the  fact  that  whenever  the  true-skin 
is  laid  bare,  as  by  a  burn  or  blister,  the  only  feeling  that  it  experi- 
ences from  contact  is  one  of  pain,  not  that  of  touch. 

19-  The  office  of  the  cuticle  is  thus  made  evident ;  it  is  to  shield 
the  nerve-filaments  from  direct  contact  with  external  objects.  At 
the  tips  of  the  fingers,  where  touch  is  most  delicate,  the  skin  rests 
upon  a  cushion  of  elastic  material,  and  receives  firmness  and  perma- 
nence of  shape  by  means  of  the  nail  placed  upon  the  less  sensitive 
side.  Besides  these  favorable  conditions,  the  form  of  the  arm  is 
such,  and  its  motions  are  so  easy  and  varied,  that  we  are  able  to 
apply  the  test  of  touch  in  a  great  number  of  directions.  The 
slender,  tapering  fingers,  with  their  pliant  joints,  together  with  the 
strong  opposing  thumb,  enable  the  hand  to  grasp  a  great  variety  of 
objects;  so  that,  great  as  are  the  delicacy  and  grace  of  the  hand,  it 
is  not  wanting  in  the  elements  of  power. 

20.  Its  beauty  and  adaptation  to  the  wants  of  man  have  made 
the  hand  an  attractive  theme  for  philosophers.  They  do  not,  how- 
ever, always  agree  in  their  conclusions.  One  has  the  opinion  that 

18.  The  sense  of  touch,  how  prevalent?    What  is  said  of  the  hand  t 

19.  Office  of  the  cuticle  ?    Tips  of  the. Angers  ?    The  fingers  with  thumb  t 
80.  What  special  importance  is  attributed  to  the  hand? 


228  THE    SPECIAL   SENSES. 

man  has  acquired  his  intelligence  and  achieved  his  place  as  "  lord 
of  creation,"  because  he  has  this  organ.  Buffon,  in  effect,  declares 
that  with  fingers  twice  as  numerous,  and  twice  as  long,  we  would 
become  proportionally  wiser;  but  Galen  long  ago  took  a  more 
reasonable  view,  when  he  taught  that  "  man  is  the  wisest  of  ani- 
mals, not  because  he  possesses  the  hand,  but  because  he  is  the 
wisest,  and  understands  its  use;  for  his  mind,  not  his  hand,  has 
taught  him  the  arts."  Another  has  well  said,  that  "  no  one  can 
study  carefully  the  human  hand  and  fail  to  be  convinced  of  the 
existence  of  the  Deity." 

21.  The    Sense    of  Touch. — Touch  is  the    simplest  of    the 
senses.     It   is   that  which  the   child  first  calls  into  exercise   in 
solving  the  early  problems  of  existence,  and  it  is  that  which  is  in 
the  most  constant  use  throughout  life.     We  are  brought  by  the 
touch  into  the  most  intimate  relations  with  external  objects,  and  by 
it  we  learn  the  greater  number,  if  not  the  most  important,  of  the 
properties  of  these  objects,  such  as  size,  figure,  solidity,  motion,  and 
smoothness  or  roughness  of  surface. 

22.  The  sense  of  touch  assists  the  other  senses,  especially  that  of 
sight,  giving  foundation  and  reality  to  their  perceptions.     Without 
it,  the  impressions  received  by  the  eye  would  be  as  vague  and 
unreal  as  the  figures  that  float  through  our  dreams.     A  boy  who 
had  been  blind  from  birth,  at  the  age  of  twelve  years  received  sight 
by  means  of  a  surgical  operation ;  at  first,  he  was  unable  to  distin- 
guish between  a  globe  and  a  circular  card  of  the  same  color  before 
he  had  touched  them.     After  that,  he  at  once  recognized  the  differ- 
ence in  their  form.     He  knew  the  peculiarities  of  a  dog  and  a  cat 
by  feeling,  but  not  by  sight,  until  one  day,  happening  to  take  up 
the  cat,  he  recognized  the  connection  of  the  two  sorts  of  impres- 
sions— those  of  touch  and  sight;  and  then,  putting  the  cat  down,  he 
said:  "  So,  puss,  I  shall  know  you  next  time." 

23.  Of  all  the  senses,  touch  is  considered  the  least  liable  to  error; 
yet,  if  that  part  of  the  skin  by  which  the  sense  is  exercised  is  removed 
from  its  customary  position,  a  false  impression  may  be  created  in  the 
mind.     This  is  well  illustrated  by  an  experiment,  which  dates  from 

21.  The  simplicity  of  touch?    What  does  it  teach  us  ? 

22.  Importance  of  the  sense  of  touch  to  the  development  of  the  other  senses  ? 

23.  Liability  of  touch  to  err  ?    Describe  the  illustration. 


THE    SPECIAL   SENSES.  229 

-,lie  time  of  Aristotle.  If  we  cross  the  middle  finger  behind  the  fore- 
linger,  and  then  roll  a  marble  or  some  small  object  upon  the  tips  of 
the  fingers  (see  Fig.  54),  the  impression  will  be  that  two  marbles 
are  felt.  If  the  fingers,  thus  transposed,  be  applied  to  the  end  of 
the  tongue,  two  tongues  will  be  felt.  When  the  nose  is  accidentally 
destroyed,  the  surgeon  sometimes  performs  an  operation  for  the 
purpose  of  forming  a  new  one,  by  transplanting  a  partially  removed 


FIG.  54. 


piece  of  the  skin  of  the  forehead  upon  the  injured  part ;  then,  if 
the  new  nose  be  touched  or  pinched,  the  feeling  is  referred  to  the 
forehead.  This  fact  illustrates  one  important  truth — that  the  nerves 
will  re-unite  after  they  have  been  cut  and  feeling  will  be  restored ; 
if  it  were  otherwise,  a  succession  of  slight  cuts  upon  the  fingers 
would  seriously  impair  their  tactile  sensibility. 

24.  The  Delicacy  of  Touch. — Although  the  hand  is  the  proper 
organ  of  this  sense,  yet  it  is  exercised  by  various  parts  of  the  body, 
their  degree  of  sensibility  being  proportional  to  the  number  of 
papillae  they  contain.  The  varying  degrees  of  tactile  delicacy  of 
the  different  parts  of  the  surface  have  been  measured  in  an  ingen- 
ious manner,  by  means  of  a  pairof  compasses,  tipped  with  small 
pieces  of  cork.  The  two  points  of  the  compasses  are  touched  at 
the  same  moment  to  the  skin,  the  eyes  being  closed,  and  it  is  found 
that,  in  sensitive  parts,  the^distance  between  the  points  may  be 
quite  slight,  and  yet  each  be  plainly  felt ;  while,  in  less  sensitive 
parts,  the  points  of  the  compasses  are  felt  as  a  single  point,  although 
they  are  separated  one  or  two  inches. 

24.  The  delicacy  of  touch  ?    Experiments  with  a  pair  of  compasses  ? 


230  THE   SPECIAL   SENSES. 

25.  At  the  tips  of  the  fingers,  the  distance  between  the  points 
being  one-twentieth  of  an  inch,  a  double  impression  is  felt.     The 
distance  must  be  twice  as  great  for  the  palm,  four  times  as  great 
for  the  lips,  and,  on  the  forehead,  it  must  be  twenty  times  greater. 
At  the  middle  of  the  back,  where  the  touch  is  least  acute,  the 
points  must  be  separated  more  than  two  inches  before  they  can  be 
separately  felt.     Therefore,  the  sense  of  touch  in  the  fingers  is  said 
to  be  fifty  times  more  delicate  than  upon  the  posterior  surface  of 
the  body. 

26.  Exquisite  delicacy  of  touch  is  attained  by  practice.     This  is 
shown  in  many  of  the  lighter  and  more  graceful  employments  of 
daily  life.     Without   it,   the   skill  of  the   painter,  sculptor,  and 
musician  would  be  rude  indeed.      By  training,  also,  the  physician 
acquires  the  tadus  eruditus,  or  discriminating  touch;  but  among  the 
blind,  delicacy  of  touch  is  most  remarkable,  and  it  there  finds  its 
highest  value ;  for  its  possession,  in  a  measure,  compensates  for  the 
loss  of  sight  by  enabling  them  to  read,  by  means  of  raised  letters,  to 
work  with  certain  tools,  and  even  to  play  upon  musical  instruments. 
A  person  born  without  sight,  and  without  hearing  or  voice,  may,  by 
the  education  of  the  touch,  be  rescued  from  apparent  imbecility,  and 
be  taught  not  only  to  read  and  write,  but  even  to  perform  household 
and  other  useful  labors. 

27.  Sensations  of  Temperature  and  Weight. — Each  of  these 
sensations  has  been  described  by  the   physiologists   as  a  special 
sense,  and  they  are  rival  candidates,  so  to  speak,  for  the  position  and 
title  of  the  sixth  sense.      In  the  sensation  of  temperature,  or  the 
thermal  sense,  touch  bears  a  part,  but  the  two  feelings  appear  to  be 
distinct.      In  proof  of  this,  we  observe,  firstly,  that  they  are  not 
alike  intense  in  the  same  situations ;  as,  for  example,  the  skin  of 
the  face  and  elbow,  where  the  sense  of  touch  is  feeble,  is  very  sensi- 
tive to   impressions  of  heat  and  cold.     Secondly,  the   ability  to 
recognize  temperature  may  be  lost  by  paralysis,  while  the  sensibility 
of  touch  remains  unaffected.    When  Une  skin  comes  in  contact  with 
a  very  hot  substance,  the   sensation  felt  is  that  of  pain — not  of 
touch.      In  like  manner,  a  very  cold  substance  causes  pain,  not  the 


25.  Further  experiments  and  results  ? 
The 
sense  ?  Give  the  two  reasons  on  the  subject 


26.  Exquisite  delicacy  of  touch  ?    The  same  among  the  blind  ? 

27.  Rival  candidates  for  the  sixth 


THE   SPECIAL   SENSES.  231 

feeling  of  cold.  So  that  a  red-hot  iron,  and  solid  carbonic  acid 
(the  temperature  of  which  is  108°  below  zero),  feel  alike;  and 
each,  if  pressed  slightly,  will  produce  a  blister.  (Read  Note  4.) 

28.  The  muscular  sense,  by  some  considered  distinct  from  touch, 
gives  rise  to  the  sensations  of  weight,  and  other  forms  of  external 
resistance.  That  this  feeling  exists,  is  shown  by  the  following 
simple  experiment :  If  the  hand  be  placed  flat  upon  a  table,  and  a 
somewhat  heavy  weight  be  put  into  it,  touch  alone  is  exercised,  and 
a  feeling  of  pressure  results ;  but  if  the  hand  be  raised,  a  certain 
amount  of  muscular  effort  must  be  put  forth,  and  thus  the  sensation 
of  weight  is  recognized.  Through  the  muscular  sense,  precision  of 
effort  is  rendered  possible ;  for  by  it  we  learn  to  adjust  the  force 
exerted  to  the  weight  of  the  object  to  be  lifted,  moved,  or  carried. 
Without  it  all  our  movements  would  necessarily  become  ill- 

4.  Qualities  Determined  by  the  Sense  of  Touch,— "The  eye,  by 

the  aid  of  certain  signs,  is  often  able  to  tell  whether  a  body  is  hot — when,  for 
instance,  it  is  glowing  or  steaming — but  a  perception  of  warmth  is  not  possessed 
by  the  eye.  This  is  had  by  the  skin  alone,  and  it  is  of  great  importance  to  our 
preservation  that  this  property  is  spread  over  the  entire  surface ;  for  it  sur- 
rounds the  body  like  a  protecting  wall  against  its  worst  enemy — cold — which,  if 
not  thus  guarded  against  at  all  points,  would  speedily  destroy  life.  We  are 
warned,  however,  of  the  approach  of  the  enemy  by  a  common  sensation  of  the 
skin,  and  an  inward  chill,  which  is  only  caused  by  a  coolness  of  the  skin.  Tha 
skin,  in  like  manner,  protects  the  body  against  the  approach  of  a  hurtful  de- 
gree of  heat.  Thus,  you  see,  the  skin  has  certain  qualities  of  sensation.  Just 
as  the  eye,  in  looking  at  a  wafer  perceives  that  it  is  both  red  and  circular, 
distinguishing  both  the  color  and  form  of  bodies,  so  the  sensitive  skin  by  con- 
tact with  an  object  distinguishes  the  qualities  of  form,  firmness,  hardness, 
liquidity,  pressure,  and  temperature.  *  *  *  Weber  has  discovered  the  in- 
teresting fact  that  warm  bodies  feel  lighter  than  cold  ones :  if  a  cold  coin  be 
placed  upon  the  forehead  of  some  person,  whose  eyes  are  shut,  and  then  upon 
the  same  spot  two  warm  coins,  the  weight  would  seem  to  him  the  same,  whilst 
he  could  distinguish  correctly  in  the  case  of  cold  weights.  *  *  *  If  we 
place  the  elbow  in  hot  water,  we  experience  heat  only  in  the  part  immersed, 
not  in  the  whole  arm,  although  the  nerve  just  under  the  skin  runs  throughout 
the  arm  and  hand.  What  we  feel  is  a  dull  sense  of  pain  in  the  whole  arm  if 
the  water  is  too  hot  So,  too,  if  the  elbow  is  placed  in  ice-water  the  pain  is 
just  the  same  in  the  arm;  proving  that  the  nerve- trunk  can  feel  neither 
warmth  nor  cold."— Bernstein's  Five  Senses  of  Man. 

28.  The  muscular  sense  ?   State  what  is  said  to  illustrate  the  subject. 


THE   SPECIAL   SENSES. 

regulated  and  spasmodic.  In  cases  of  disease,  where  the  sensibility 
of  the  lower  limbs  is  lost  while  power  of  motion  remains,  the  patient 
is  able  to  stand  erect  so  long  as  he  can  see  his  limbs ;  but  just  as 
soon  as  his  eyes  are  closed,  he  begins  to  waver,  and  will  fall  unless 
supported. 

29.  The  Organ  of  Taste. — The  tongue  is  the  special  organ  of 
the  sense  of  taste ;  but  the  back  part  of  the  mouth  always  possesses 
this  faculty.    The  tongue  is  a  muscular  organ,  the  muscles  composing 
it  being  so  numerous  and  interwoven  as  to  give  it  the  freedom  and 
variety  of  motion  which  it  possesses.     It  can  curve  itself  upward  or 
downward ;  it  can  extend  or  contract  itself ;  and,  with  its  point,  can 
sweep  the  cavity  of  the  mouth,  in  all  directions,  in  the  search  for 
scattered  particles  of  food. 

30.  The  upper  surface  of  the  tongue  is  peculiar,  being  marked  by 
the   presence   of    innumerable   papillce,   some    of    which  are   of 
microscopic  size,  resembling  those  that  abound  in  the  fingers,  and  in 
other  parts  of  the  body  that  have  the  sense  of  touch.      Others  are 
much  larger,  and  give  to  the  tongue  its  roughness  of  feeling  and 
appearance.     Through  the  medium  of  these  papillae,  the  tongue  re- 
ceives impressions  of  touch  and  temperature,  as  well  as  taste :  indeed, 
its  extremity  is  fully  as  delicate,  in  respect  to  tactile  sensations,  as 
the  tips  of  the  fingers  themselves.     It  can  recognize  the  two  points 
of  the  compasses  when  separated  not  more  than  one  twenty-fourth 
of  an  inch  ;  the  back  of  it  is  much  less  sensitive  to  touch,  while  at 
the  same  time  it  is  more  highly  sensitive  to  impressions  of  taste. 

31.  Each  lateral   half  of  the   tongue   resembles  the   other  in 
structure,  and  each  receives  the  same  number  of  nerves — three.    One 
of  these  regulates  motion,  the  other  two  are  nerves  of  special  sense. 
One  of  the  latter  supplies  the  fiont  half  of  the  tongue,  and  is  called 
the  gustatory  nerve.     This  is  a  branch  of  the  great  cranial  nerve, 
called  the  "  fifth  pair,"  which  ramifies  in  all  parts  of  the  face.    The 
back  of  the  tongue  is  endowed  with  the  power  of  taste,  through  a 
nerve  known  as  the  glosso-pharyngeal,  because  it  is  distributed  both 
to  the  tongue  and  throat.      This  difference  in  the  nervous  supply 
of  the  tongue  becomes  significant,  when  we  learn,  as  we  shall 

29,  The  organ  of  taste  ?    The  tongue  ?    Its  powers  of  motion  ? 

80.  Peculiarities  of  the  tongue  ?    Uses  of  the  papillae  ? 

81.  Resemblance  to  the  parts  of  the  tongue  ?    Powers  and  functions  of  the  parts  '( 


THE   SPECIAL   SENSES.  233 

presently,   that    each    part   of  it    perceives  a   different   class   of 
flavors. 

32.  The  Sense  of  Taste. — Taste  is  the  special  sense  by  means 
of  which  we  discover  the  savors,  or  flavoring  properties  of  the  sub- 
stances which  come  in  contact  with  the  tongue.     Mere  contact  with 
the  surface  of  the  tongue,  however,  is  not  sufficient,  but  contact 
with  the  extremities  of  the  nerves  of  taste  within  the  papillae  is  re- 
quired.    In  order  that  the  substance  to  be  tasted  may  penetrate  the 
cells  covering  the  nerves,  it  must  either  be  liquid  in  form,  or  readily 
soluble  in  the  watery  secretion  of  the  mouth — the  saliva.      The 
tongue  must  be  moist  also.     If  the  substance  be  insoluble — as  glass 
or  sand — or  the  tongue  dry,  the  sense  of  taste  is  not  awakened. 
In  sickness,  when  the  tongue  is  heavily  coated,  the  taste  is  very 
defective,  or,  as  is  frequently  expressed,  "nothing  tastes  aright." 

33.  All  portions  of  the  tongue  are  not  alike  endowed  with  the 
sense  of  taste,  that  function  being  limited  to  the  posterior  third,  and 
to  the  margin  and  tip  of  this  organ.     The  soft  palate,  also,  possesses 
the  sense  of  taste ;  hence,  an  article  that  has  an  agreeable  flavor 
may  very  properly  be  spoken  of  as  palatable,  as  is  often  done.     All 
parts  of  the  tongue  do  not  perceive  equally  well  the  same  flavors. 
Thus,  the  front  extremity  and  margin,  which  is  the  portion  supplied 
by  the  "  fifth  pair  "  of  nerves,  perceives  more  acutely  sweet  and  sour 
tastes ;  but  the  base  of  the  tongue,  supplied  by  the  glosso-pharyngeal 
nerve,  is  especially  sensitive  to  salt  and  bitter  substances.     The 
nerve  of  the  front  part  of  the  tongue,  as  before  stated,  is  in  active 
sympathy  with  those  of  the  face,  while  the  relations  of  the  other 
nerve  are  chiefly  with  the  throat  and  stomach ;  so  that  when  an 
intensely  sour  taste  is  perceived,  the  countenance  is  involuntarily- 
distorted,  and  is  said  to  wear  an  acid  expression.     On  the  other 
fiand,   a   very  bitter  taste  affects    certain    internal   organs,   and 
occasions  a  sensation    of    nausea,   or   sickness  of  the   stomach. 
(Read  Note  5.) 

5.  Flavors  and  the   Sense  of  Taste. — "The  cause  and    intimate 
nature  of  tastes  are  no  better  understood  than  those  of  odors.     Flavors 


82.  Taste?    What  are  the  requisites  to  taste ? 

83.  Portions  of  the  tongue  endowed  with  taste  ?    Where  else  does  the  sense  lodge?  What 
'&  stated  in  respect  to  sweet  and  bitter  flavors  ?    Reflex  effects  mentioned  ? 


234  THE   SPECIAL  SENSES. 

34.  Relations  of  Taste  with  other  Senses.— Taste  is  not  a 

simple  sense.  Certain  other  sensations,  as  those  of  touch,  tempera- 
ture, smell,  and  pain,  are  blended  and  confused  with  it ;  and  certain 
so-called  tastes  are  really  sensations  of  another  kind.  Thus  an 
astringent  taste,  like  that  of  alum,  is  more  properly  an  astringent 
feeling,  and  results  from  an  impression  made  upon  the  nerves  of 
touch,  that  ramify  in  the  tongue.  In  like  manner,  the  qualities 
known  as  smooth,  oily,  watery,  and  mealy  tastes,  are  dependent 
upon  these  same  nerves  of  touch.  A  burning  or  pungent  taste  is  a 
sensation  of  pain,  having  its  seat  in  the  tongue  and  throat.  A  cool- 
ing taste,  like  that  of  mint,  pertains  to  that  modification  of  touch 
called  the  sense  of  temperature. 

35.  Taste  is  largely  dependent  upon  the  sense  of  smell     A  con- 
siderable number  of  substances,  like  vanilla,  coffee,  and  garlic, 
which  appear  to  possess  a  strong  and  distinct  flavor,  have  in  reality 
a  powerful  odor,  but  only  a  feeble  taste.     When  the  sense  of  smell 

elude  analysis  and  defy  classification,  even  that  which  divides  them  into 
agreeable  and  disagreeable,  for  the  taste  of  individuals  and  of  nations 
singularly  differs  in  this  respect.  The  Laplander  and  the  Esquimaux 
drink  great  quantities  of  train-oil,  which  for  them  is  a  greatly-esteemed 
article  of  food,  and  is  most  admirably  adapted  to  the  exigencies  of  a  Polai 
climate  ;  the  Abyssinians  eat  raw  flesh,  and  find  its  flavor  excellent,  while 
the  inhabitant  of  the  "West  partakes  of  it  with  the  greatest  repugnance 
and  only  as  a  medicine.  Oysters,  which  are  so  generally  esteemed  in 
our  country,  are  to  some  persons  disagreeable  and  nauseous ;  and  truffles, 
the  delight  of  the  gourmand,  are  rejected  by  the  uninitiated  on  account 
of  their  flavor  and  their  perfume.  It  is  the  same  with  almost  all  alimentary 
substances ;  they  are  eagerly  sought  after  by  some,  and  despised  or 
abhorred  by  others.  Let  us  remember  the  proverb  '  de  gustibus  non 
disputandum,'  and  not  dispute  in  regard  to  tastes;  each  is  suited  to  its 
own  country,  and  goodly  numbers  acclimatize  themselves,  to  the  great 
advantage  of  peoples  among  whom  at  first  they  seem  exceedingly  strange. 
Man  should  control  his  taste,  and  habituate  it  to  all  wholesome  aliment ; 
this  neither  excludes  choice,  nor  blunts  the  delicacy  of  the  sense ;  and 
while  we  resist  its  seductions,  we  should  give  timely  heed  to  its  instincts 
and  its  counsels,  for  they  are  often  invaluable." — The  Wonders  of  the  Human 
Body. 


84.  What  is  stated  of  the  relations  of  taste  to  other 

85.  Its  dependence  on  gmellf  on  eight? 


THE   SPECIAL    SENSES.  235 

is  interfered  with  by  holding  the  nose,  it  becomes  difficult  to  dis- 
tinguish between  substances  of  this  class.  The  same  effect  is  fre- 
quently observed  when  smell  is  blunted  during  an  ordinary  cold  in 
the  head.  Sight  also  contributes  to  taste.  With,  the  eyes  closed, 
food  appears  comparatively  insipid ;  and  a  person  smoking  tobacco 
in  the  dark  is  unable  to  determine  by  the  taste  whether  his  cigar  is 
lighted  or  not.  Accordingly,  it  is  not  a  bad  plan  to  close  the  nose 
and  shut  the  eyes  when  about  to  swallow  some  disagreeable  medi- 
cine. 

36.  Influence  of  Education  on  the  Taste. — The  chief  use  of 
the  sense  of  taste  appears  to  be  to  act  as  a  guide  in  the  selection  of 
proper  food.     Hence  its  organs  are  properly  placed  at  the  entrance 
of  the  digestive  canal.      As  a  general  rule,  those  articles  which 
gratify  the  taste  are  wholesome ;  while  the  opposite  is  true  of  those 
which  impress  it  disagreeably.     This  statement  is  more  exact  in 
reference  to  the  early  than  to  the  later  years  of  life,  when,  by  reason 
of  improper  indulgence,  the  sense  of  taste  has  become  dulled  or  per- 
verted.    The  desires  of  a  child  are  simple ;  he  is  fully  satisfied  with 
plain  and  wholesome  articles  of  diet,  and  must  usually  "  learn  to 
like  "  those  which  have  a  strongly  marked  flavor.     Accordingly,  it 
is  far  easier  at  this  age  to  encourage  the  preference  for  plain  food, 
and  thus  establish  healthful  habits,  than  later  in  life  to  uproot 

^habits  of  indulgence  in  stimulating  substances,  after  their  ill  effects 
begin  to  manifest  themselves. 

37.  The  tastes  of  men  present   the  most  singular  diversities, 
partly  the  result  of  necessity  and  partly  of  habit  or  education. 
The  Esquimaux  like  the  rank  smell  of  whale-oil,  which  is  a  kind  of 
food  admirably  suited  to  the  requirements  'of  their  icy  climate ;  and 
travelers  who  go  from  our  climate  to  theirs  are  not  slow  to  develop 
a  liking  for  the  same  articles  that  the  natives  themselves  enjoy. 
The  sense  of  taste  is  rendered  very  acute  by  education,  as  is  shown 
in  an  especial  manner  by  those  who  become  professional  "  tasters  " 
of  tea  and  wine. 

38.  The  Sense  of  Smell— the  Nasal  Cavities.— The  sense  of 
, __ 

86.  The  chief  use  of  the  sense  of  taste  ?    The  position  of  its  organs  ?    The  rule  as  regardo 
wholesome  and  unwholesome  food  ?    Remarks  respecting  the  rule  t 

37.  Diversity  in  tastes  of  men  J    How  shown  ?    The  education  of  the  sense  of  tftSfa? 

88.  LocatioB  of  tto  KUM  of  eroeU  ?   Tb«  nose  ?   "  Roof  $  tUe  isoutb  ?" 


236  THE  SPECIAL   SENSES. 

smell  is  located  in  the  delicate  mucous  membrane  which  lines  the 
interior  of  the  nose.  That  prominent  feature  of  the  face,  the  nose, 
which  is  merely  the  front  boundary  of  the  true  nasal  organ,  is  com* 
posed  partly  of  bone  and  partly  of  cartilage.  The  upper  part  of  it 
is  united  with  the  skull  by  means  of  a  few  small  bones,  to  which 
circumstance  is  due  its  permanence  of  shape.  The  lower  portion, 
or  tip  of  the  nose,  contains  several  thin  pieces  of  cartilage  which 
render  it  flexible  and  better  able  to  resist  the  effects  of  blows  and 
pressure.  Behind  the  nose  we  find  quite  a'  spacious  chamber, 
separated  from  the  mouth  by  the  hard  palate,  forming  the  "  roof 
of  the  mouth,"  and  also  by  the  soft  palate  (see  Fig.  55) ;  and 
divided  into  two  cavities  by  a  central  partition  running  from  before 
backward. 

39.  These  nasal-  cavities,  constituting  the  true  beginning  of  the 
air-passages,  extend  from  the  nose  backward  to  the  upper  opening 
of  the  throat,  and  rise  as  high  as  the  junction  of  the  nose  with  the 
forehead.     The  inner  wall  of  each  cavity  is  straight  and  smooth ; 
but  from  the  outer  wall  there  jut  into  each  cavity  three  small  scroll- 
like  bones.     The  structure  of  these  bones  is  very  light,  and  hence 
they  have  been  called  the  "  spongy  "  bones  of  the  nose.     In  this 
manner,  while  the  extent  of  surface  is  greatly  increased  by  the  for- 
mation of  these  winding  passages,  the  cavities  are  rendered  extremely 
narrow ;  so  much  so,  in  fact,  that  a  moderate  swelling  of  the  mucous 
membrane  which  lines  them,  as  from  a  cold,  is  sufficient  to  obstruct 
the  passage  of  air  through  them. 

40.  The  Nerve  of  Smell. — The  internal  surface  of  the  nasal 
passages  is  covered  by  a  delicate  and  sensitive  mucous  membrane. 
Its  surface  is  quite  extensive,  following  as  it  does  all  the  inequali- 
ties produced  by  the  curved  spongy  bones  of  the  nose.     Only  the 
upper  portion  of  it  is  the  seat  of  smell,  since  that  part  alone  re- 
ceives branches  from  the  "first  pair"  of  cranial  nerves,  or  the 
olfactory  nerve,  which  is  the  special  nerve  of  smell  (see  Fig.  55). 
In  Fig.  55  is  shown  the  distribution  of  this  nerve,  in  the  form  of 
an  intricate  network  upon  the  two  upper  spongy  bones.     The  nerve 
itself  (1)  does  not  issue  from  the  skull,  but  rests  upon  a  thin  bone 

89.  Cavltteg  of  the  nose  T    Obstruction  of  the  passage  of  air  through  them  ? 
40.  The  special  nerve  of  smell  ?    Its  location  ? 


THE   SPECIAL  SENSES. 


237 


FIG.  55.— SECTION  OF  THE  EIGHT  NASAL  CAVITY. 


which  separates  it  from  the  cavity  of  the  nose ;  and  the  branches 
which  proceed  from  it  pass  through  this  bone  by  means  of  numer- 
ous small  openings.  The  engraving  represents  the  outer  surface  of 
the  right  nasal  cavity ;  the  three  wave-like  inequalities,  upon  which 
the  nervous  network  is  spread  out,  are  due  to  the  spongy  bones. 
The  left  cavity  is  supplied  in  the  same  manner. 

41.  The    nerves    which 
ramify  over  the  lower  part 
of  the  membrane,  and  which 
endow  it  with  sensibility  to 
touch  and  pain,  are  branches 
of  the  "fifth  pair"  of  nerves. 
An  irritation  applied  to  the 
parts   where  this  nerve  is 
distributed  occasions  sneez-' 
ing — that  is,   a   spasmodic 
contraction     of     the     dia- 
phragm, the  object  of  which 

is  the  expulsion  of  the  irritating  cause.  The  manner  in  which  the 
olfactory  nerve-fibres  terminate  is  peculiar.  Unlike  the  extremities 
of  other  nerves,  which  are  enclosed  by  a  greater  or  less  thickness  of 
tissue,  these  come  directly  to  the  surface  of  the  mucous  membrane, 
and  thus  are  in  very  close  contact  with  the  odorous  particles  that 
are  carried  along  by  the  respired  air.  The  surface  is  at  all  times 
kept  in  a  moist  condition  by  an  abundant  flow  of  nasal  mucus ; 
otherwise  it  would  become  dry,  hard,  and  insensitive  from  the  con- 
tinual passage  of  air  to  and  fro  in  breathing.  Birds,  which  respire, 
more  actively  than  men,  have  a  special  gland  for  secreting  a  lubri- 
cating fluid,  located  in  the  air-passages  of  the  head. 

42.  The  Uses  of  the  Sense  of  Smell. — Smell  is  the  special 
sense  which  enables  us  to  appreciate  odors.     Touch,  as  we  have 
seen,  is  largely  concerned  with  solid  bodies,  and  taste  with  fluids, 
or  with  solids  in  solution.     Smell,  on  the  other  hand,  is  designed 
to  afford  us  information  in  reference  to  substances  in  a  volatile  or 
gaseous  form.     Invisible  particles  issue  from  odorous  bodies  and 


41.  Branches  of  the  "  fifth  pair"  of  nerves  ?    Nasal  mucus  ?    Birds  ? 

42.  Smell?    Touch?    Taste?    Design  of  smell ?    Invisible  and  gaseous  particles?    The 
extreme  fineness  of  the  particles  ?    Musk  ?    In  other  cases  ? 


238  THE   SPECIAL  SENSES. 

are  brought  by  the  respired  air  in  contact  with  the  terminal  fita 
ments  of  the  olfactory  nerve,  upon  which  an  agreeable  or  disagree- 
able impression  is  produced.  The  fineness  of  the  particles  that 
constitute  odors  is  often  so  extreme  that  they  elude  all  attempts 
to  measure  or  weigh  them.  A  piece  of  musk,  for  instance,  may  be 
kept  for  several  years,  constantly  emitting  perfume  without  any 
appreciable  loss  of  weight.  In  other  cases,  a  loss  of  substance  is 
perceptible,  as  in  the  essential  oils,  which  enter  into  the  composi- 
tion of  the  ordinary  perfumes. 

43.  Smell,  like  taste,  aids  us  in  the  choice  of  proper  food,  lead- 
ing us  to  reject  such  articles  as  have  a  rank  or  putrid  odor,  and 
which  are,  as  a  rule,  unfit  to  be  eaten.  The  highest  usefulness  of 
this  sense,  however,  consists  in  the  protection  it  affords  to  the 
organs  of  respiration.  Stationed  at  the  gateways  of  the  air-passages, 
it  examines  the  current  of  air  as  it  enters,  and  warns  us  of  the 
presence  of  noxious  gases,  and  of  other  and  generally  invisible 
enemies  to  health.  Not  all  dangerous  vapors  are  offensive,  but  al- 
most all  offensive  vapors  are  unfit  to  be  breathed.  A  number  of 
small  stiff  hairs  grow  from  the  margin  of  the  nostrils  to  prevent 
the  entrance  of  dust  and  other  atmospheric  impurities,  which  would 
be  alike  injurious  to  the  olfactory  mucous  membrane  and  to  the 
lungs.  The  benevolent  design  of  the  Maker  of  our  bodies  may  be 
observed  in  all  parts  of  their  mechanism  ;  but,  probably,  in  none  is 
it  more  clearly  displayed  than  in  connection  with  the  sense  of  smell 
(Read Note  b.) 

6.  The  Protective  Function  of  the  Sense  of  Smell.— "Smell 

seems  to  be  regarded  as  an  endowment  bestowed  simply  for  pleasure,  serving 
to  promote  no  important  or  vital  end.  That  its  main  use  is  to  signal  danger 
to  internal  parts  is  not  duly  appreciated  The  detection  of  an  offensive  odoi 
is  thought  to  be  the  only  bad  thing  about  it,  and  which,  to  those  habituated 
to  it,  is  of  no  subsequent  importance.  Men  even  pride  themselves,  on  becom- 
ing accustomed  to  offensive  odors,  and  quite  enjoy  the  sight  of  one  whose  nerve 
of  smell  is  not  benumbed  like  their  own.  Instead  of  seeking  to  blunt  the 
sensibilities  of  this  nerve,  it  should  be  a  study  to  improve  it,  as  the  most  deli- 
cate and  available  test  of  air  impurity — far  superior,  under  ordinary  circum- 
stances, to  the  tests  of  science.  In  this  way,  all  ordinary  atmospheric  impu- 
rities may  be  quickly  detected ;  and  it  is  truly  remarkable  how,  by  a  little 
attention,  this  sense  can  be  so  improved  as  to  detect  instantly  even  slight  im,< 
48,  A  i<3  given  by  •aeU  ?  The  mgfcest  use  of  the  sense  ?  Explain  the  manner, 


THE   SPECIAL   SENSES.  239 

44.  The  sense  of  smell  is  developed  in  a  remarkable  degree  in 
certain  of  the  inferior  animals,  and  is  especially  acute  in  reference 
to  the  peculiar  odors  that  characterize  the  different  animals.  The 
lion  and  other  carnivorous  beasts  scent  their  prey  from  a  great  dis- 
tance ;  and  the  fox-hound  is  able  to  track  the  fox  through  thickets 
and  over  open  country  for  many  miles ;  while  the  timid,  helpless 
herbivora,  such  as  the  deer  and  sheep,  find  in  the  sense  of  smell  a 
means  of  protection  against  their  natural  enemies,  of  whose  approach 
they  are  in  this  manner  warned.  By  training  this  sense  in  the  dog, 
and  making  it  subservient  to  his  use,  man  is  able  to  hunt  with  suc- 
cess certain  shy  and  very  fleet  animals,  which  otherwise  he  could 
but  seldom  approach.  Among  men,  individuals  differ  greatly  in 
respect  to  the  development  of  this  sense  ;  and  especially  in  certain 
savage  tribes  it  is  found  to  be  extremely  delicate.  Humboldt  states 
that  the  natives  of  Peru  can  by  it  distinguish  in  the  dark  between 
persons  of  different  races.  (Read  Note  7.) 

purities  to  which  it  had  before  been  insensible.  In  many  houses,  by  the  total 
neglect  of  this  sense,  there  is  an  ever-present  family  odor,  produced  by  some 
special  kind  of  household  impurity,  and  of  which  the  inmates  do  not  seem  to 
be  aware.  To  those  accustomed  to  pure  air,  house  odors  are  always  perceptible 
and  disagreeable.  This  ought  to  be  accepted  as  sufficient  evidence  of  their 
unhealthful  tendencies  ;  not  perhaps  of  an  instant  or  violent  sort,  yet  enough  so 
to  give  rise  to  many  sensations  of  slight  discomfort,  and  producing,  when  long 
continued,  a  state  of  the  body  very  favorable  to  the  beginning  and  growth  of 
virulent  diseases." — Black's  Ten  Laws  of  Health. 

7.  The  Effects  of  Certain  Odors.—"  I  have  not  seen  it  anywhere  laid 
down  as  a  general  rule,  but  I  believe  it  might  be  affirmed,  that  we  are  intended 
to  be  impressed  only  sparingly  and  transiently  by  odor.  There  is  a  provision 
for  this  in  the  fact  that  all  odors  are  vapors  or  gases,  or  otherwise  volatile  sub- 
stances ;  so  that  they  touch  but  the  inside  of  the  nostril,  and  then  pass  away. 

"In  conformity  with  this  fleeting  character  of  odorous  bodies,  it  is  a  law  in 
reference  to  ourselves,  to  which,  as  far  as  I  know,  there  is  no  exception,  that 
there  is  not  any  substance  having  a  powerful  smell  of  which  it  is  safe  to  take 
much  internally.  The  most  familiar  poisonous  vegetables,  such  as  the  poppy, 
hemlock,  henbane,  monk's-hood,  and  the  plants  containing  prussic  acid,  have 
all  a  strong  and  peculiar  smelL  Nitric,  muriatic,  acetic,  and  other  corrosive 
acids,  have  characteristic  potent  odors,  and  all  are  poisons.  Even  bodies  with 
agreeable  odors,  like  oil  of  roses,  or  cinnamon,  or  lavender,  are  wholesome  only 
in  very  small  quantities,  and,  when  the  odor  is  repulsive,  only  in  the  smallest 

44.  Sense  of  smell  in  the  inferior  animals  9    How.  and  in  what  cases,  illustrated  ? 


"HE    Sl'KClAL    SENSES. 

45.  The  Sense  of  Sight. — Sight,  or  vision,  is  the  special  sense 
by  means  of  which  we  appreciate  the  color,  form,  size,  distance,  and 
other  physical  properties  of  the  objects  of  external  nature.   Primarily, 
this  sense  furnishes  us  with  information  concerning  the  different 
shades  of  color  and  the  different  degrees  of  brightness :  these  are 
the  simple  sensations  of  sight,  such  as  the  yellowness  and  glitter  of 
a  gold  coin.     In  addition  to  these,  there  are  composite  visual  sen- 
sations, produced  by  the  joint  action  of  the  other  senses  and  by  the 
use  of  the  memory  and  judgment ;  such  as,  in  the  case  of  the  coin, 
its  roundness,  solidity,  size,  its  distance  and  direction  from  us.     So 
that  many  of  our  sensations,  commonly  considered  as  due  to  sight, 
are  in  reality  the  results  of  intellectual  processes  which  take  place 
instantaneously  and  unconsciously. 

46.  This  faculty  not  only  is  valuable  in  the  practical  e very-day 
affairs  of  life,  but  it  contributes  so  largely  to  the  culture  of  the 
intellect  and  to  our  higher  forms  of  pleasure,  that  some  writers  are 
disposed  to  rate  it  as  the  first  and  most  valuable  of  the  senses. 
Others,  however,  maintain  that  the  sense  of  hearing  does  not  yield 
in  importance  to  that  of  sight ;  and  they  cite  in  support  of  their 
position  the  fact  that  the  blind  are  commonly  cheerful  and  gay, 
while  the  deaf  are  inclined  to  be  morose  and  melancholy.     In  re- 
spect to  the  relative  capacity  for  receiving  education  in  the  deaf  and 
blind,  it  is  found  that  the  former  learn  more  quickly,  but  their  at- 
tainments are  not  profound ;  while  the  blind  acquire  more  slowly, 
but  are  able  to  atudy  more  thoroughly. 

47.  Light — The  Optic  Nerve  .^-Unlike  the  senses  previously 
considered — touch,  taste,  and  sme^l — sight  does  not  bring  us  into 

quantities.  So  far  as  health  is  concerned,  the  nostril  should  be  but  sparingly 
gratified  with  pleasing  odors  or  distressed  by  ungrateful  ones.  No  greater 
mistake  can  be  made  in  sick-rooms  than  dealing  largely  in  aromatic  vinegar, 
eau  de  cologne,  lavender  water,  and  other  perfumes.  This  hiding  of  one  odor 
by  another  is  like  trying  to  put  away  the  taste  of  bitter  aloes  by  that  of  Epsom 
salts.  Physical  comfort  is  best  secured  by  rarely  permitting  an  infraction  of 
the  rule  that  the  condition  of  health  is  no  odor  at  alL"— Wilson  on  the 


45.  What  is  sight?    What  information  does  it  furnish?    Composite  visual  sensations? 

46.  Comparison  between  sight  and  hearing  ?    Kelative  capacity  of  deaf  and  blind. 

47.  Sight,  unlike  the  other  senses  ?    In  the  case  of  the  stars  2 


THE    SPECIAL   SENSES.  241 

immediate  contact  with  the  bodies  that  are  examined ;  but,  by  it, 
we  perceive  the  existence  and  qualities  of  objects  that  are  at  a 
greater  or  less  distance  from  us.  In  the  case  of  the  stars,  the  dis- 
tance is  incalculable,  while  the  book  we  read  is  removed  but  a  few 
inches.  Light  is  the  agent  which  gives  to  this  sense  its  wide  range. 
The  nature  of  this  mysterious  force  is  not  known,  and  it  is  not  here 
to  be  discussed,  since  its  stwjy  belongs  more  properly  to  the  prov- 
ince of  natural  philosophy.^  \ 

48.  It  is  sufficient,  in  this  connection,  to  state  that  the  theory 
of  light  now  generally  accepted,  and  which  best  explains  the  facts 
of  optics,  is  that  known  as  the  undulatory  theory.     This  theory 
supposes  that  there  exists  an  intangible,  elastic  medium,  which  fills 
all  space,  and  penetrates  all  transparent  substances,  and  which  is 
thrown  into  exceedingly  rapid  undulations  or  waves,  by  the  sun 
and  every  other  luminous  body — the  undulations  being  propagated 
with  extreme  rapidity,  and  moving  not  less  than  186,000  miles  in 
a  second. 

49.  These  waves  are  thought  to  produce  in  the  eye  the  sensation 
of  light,  in  the  same  manner  as  the  sonorous  vibrations  of  the  air 
produce  in  the  ear  the  sensation  of  sound.     That  part  of  the  eye 
which  is  sensitive  to  these  waves  is  the  expansion  of  the  optic 
nerve.     It  is  sensitive  to  no  other  impression  than  that  of  light,  and 
it  is  the  only  nerve  which  is  acted  upon  by  this  agent.     The  optic 
nerve,  also  called  the  "second  pair"  of  cranial  nerves,  is  the  means 
of  communication  between  the  eye  and  the  brain. 

50.  The  two  nerves  constituting  the  pair  arise  from  ganglia 
lying  at  the  base  of  the  cerebrum — one  of  them  on  each  side — from 
which  points  they  advance  to  the  eyes,  being  united  together  in  the 
middle  of  their  course  in  the  form  of  the  letter  X  (Fig.  51-2). 
By  this  union  the  two  eyes  are  enabled  to  act  harmoniously,  and  in 
some  respects  to  serve  as  a  double  organ.     By  reason  of  this  same 
intimate  nervous  communication,  when  serious  disease  affects  one 
eye,  the  fellow-eye  is  extremely  liable  to  become  the  seat  of  sym- 
pathetic inflammation ;  and  this,  if  neglected,  almost  certainly  re- 
sults in  hopeless  blindness. 

48.  The  undulatory  theory  of  light?    What  does  the  theory  suppoie? 

49.  The  sensation  of  light?    Optic  nerve? 

60.  The  two  nerves  constituting  the  pair  of  nerves? 

11 


THE    SPECIAL    SENSES. 

51.  The  Organ  of  Sight — The  Eye. — The  proximity  of  the 
eye  to  the  brain,  and  the  important  part  it  performs  in  giving  ex- 
pression to  the  emotions,  have  given  it  the  name  of  "  the  window 
of  the  soul."     The  exceeding  beauty  of  its  external  parts,  and  the 
high  value  of  its  function,  have  long  made  this  organ  the  subject  of 
enthusiastic  study.     It  is  chiefly  within  the  last  twenty  years,  how- 
ever,  that  this  study  has  been  successful  and  fruitful  of  practical 
results.     Several  ingenious  instruments  have  been  invented  for  the 
examination  of  the  eye  in  health  and  disease,  and  new  operations 
have  been  devised  for  the  relief  of  blindness  and  of  impaired  vision. 
As  a  result,  it  is  now  a  well-marked  fact  that,  in  civilized  lands,  the 
number  of  those  who  suffer  from  loss  of  sight  is  proportionally  much 
less  than  in  countries  where  science  is  less  known  and  cultivated. 

52.  The  most  obvious  fact  in  respect  to  the  apparatus  of  sight  is 
that  there  are  two  eyes,  which  may  either  act  together  as  one,  and 
be  fixed  upon  one  object,  or  one  eye  may  be  used  independently  of 
the  other.     In  consequence  of  this  arrangement,  the  loss  of  one  eye 
does   not  necessitate  blindness,  and,  in  fact,  it  not  infrequently 
happens  that  the  sight  of  one  eye  may  be  long  impaired  or  lost  be- 
fore the  fact  is  discovered.     We  next  notice  that  it  is  placed  at  the 
most  elevated  part  of  the  body,  in  front,  and  near  the  brain.     It 
also  commands  a  wide  range  of  view,  being  itself  moved  with  great 
rapidity,  and  being  further  aided  by  the  free  motion  of  the  head 
and  neck.     The  organ  of  vision  consists  essentially  of  two  parts : 
the  optical  instrument  itself — the  eyeball — and  its  enveloping  parts, 
or  the  case  in  which  the  instrument  is  kept  free  from  harm.     The 
latter,  which  are  external,  and  which  we  shall  first  consider,  are 
chiefly  the  orbits,  the  eyelids,  and  the  apparatus  for  the  tears. 

53.  The  Orbits. — The  eyeball,  which  is  a  delicate  organ,  is 
well  defended  against  external  injury  within  the  orbits  or  bony 
sockets  of  the  head.     These  are  deep  conical  hollows,  bounded  in 
part  by  the  bones  of  the  skull,  and  in  part  by  those  of  the  nose  and 
cheek.     The  orbit  juts  out.  beyond  the  most  exposed  portion  of  the 

51.  Why  is  the  eye  called  the  ••  window  of  the  soul  ?"    Why  the  subject  of  enthusiastic 
study? 

52.  The  most  obvious  fact?     The  consequence?     The  next  thing  noticed?    Its  range 
of  view  ?    Of  what  does  the  organ  of  vision  consist? 

53.  The  protection  of  the  eyeball  against  injury  f    The  overhanging  brow?    The  opening 
for  the  optic  nerve? 


THE   SPECIAL   SENSES.  243 

eyeball,  as  may  be  seen  by  laying  a  book  over  the  eye,  when  it  wiD 
be  found  that  no  part  of  the  eyeball,  unless  it  be  very  prominent, 
will  be  touched  by  the  book  ;  so.  that  the  only  direction  in  which 
an  injury  is  liable  to  be  received  is  immediately  in  front  of  the  eye. 
The  overhanging  brow  is  itself  covered  by  a  layer  of  thick  skin, 
studded  with  short,  stout  hairs,  which  are  so  bent  as  to  prevent 
the  perspiration  from  running  into  the  eye  and  obscuring  vision. 
Through  a  hole  in  the  bottom  of  the  orbit,  the  nerve  of  sight  passes 
outward  from  the  brain.  The  orbit  also  contains  a  considerable 
amount  of  a  fatty  tissue,  upon  which,  as  upon  an  elastic  cushion, 
the  eye  rests. 

54.  The  Eyelids.  —  The  eyelids  are  two  movable  curtains,  or 
folds,  which,  when  shut,  cover  the  front  part  of  the  orbit,  and  hide 

the  eye  from  view.  The  upper 
lid  is  the  larger,  has  a  curved 
margin,  and  moves  freely,  whilb 
the  lower  lid  is  comparatively 
short  and  straight,  and  has  but 
a  slight  degree  of  motion  (Fig. 
56).  Skin  covers  the  exterior 
of  the  lids,  while  a  fine  mucous 
membrane  lines  their  inner  sur- 
face, and  is  likewise  spread  out 

RlGHT  EY*  over  the    entire   front  of   the 
lyin8  **"  eJeta11-    Tnis  membrane,  which 

2.  The  Nasal  Duct  is  shown  by  the  dotted  line,    is  called  the  Conjunctiva,  IS  highly 
The  *  marks  the  orihce  in  the  lower  lid.  '     * 

The  central  black  spot  is  the  pupil;  sur-  sensitive,  and  thus  plays  an  im- 

it  is  the  iris;  and  the   triangular 


roundmg 
white  s 


white  spaces  are  the  visible  portion  of  the   portant   part   in     protecting    the 


eye  against  the  lodgment  of  sand, 
ashes,  chaff,  and  other  foreign  particles  that  are  blown  about  in  the 
air.  This  sensitive  membrane  will  not  endure  the  presence  of 
these  particles.  If  any  find  access,  it  causes  a  constant  winking, 
a  flow  of  tears,  and  other  signs  of  irritation,  until  it  is  removed. 
Read  Note  8.) 

8.    How    to    Remove    Foreign  Bodies    from    the    Eye.—  "Lay 

your  finger  on   the  cheek,  and  draw  the  lower  lid  gently  down,  while  the 

54.  What  are  the  eyelids?    The  upper  lid  ?    The  lower  one  *    The  mucous  membrane  of 
the  eye? 


244  THE   SPECIAL   SENSES. 

55.  The  long,  silky  eyelashes,  which  garnish  the  edges  of  the 
lids,  act  like  a  sieve  to  prevent  the  entry  of  dust  and  other  irri- 
tants ;  and  together  with  the  lids,  they  regulate  the  amount  of  light 
which  is  permitted  to  enter  the  eye,  so  that  it  is  shielded  from  a 
sudden  flood  or  glare  of  light.     The  little  points  seen  in  the  figure 
just  within  the  line  of  the  lashes,  especially  on  the  lower  lid,  repre- 
sent the  mouths  of  numerous  little  sebaceous  glands  (Fig.  57,  D,  D), 
such  as  are  always  found  in  the  neighborhood  of  hairs.     These 
glands  supply  a  thick,  oily  material  which  greases  the  edges  of  the 
lids  and  prevents  their  adhering  together,  and  likewise  prevents  the 
overflow  of  the  tears  upon  the  cheek. 

56.  The  Lachrymal  Fluid,  or  the  Tears. — Just  within  the 
outer  part  of  the  bony  arch  of  the  brow,  where  the  bone  may  be 
felt  to  be  sharper  than  in  other  positions,  is  lodged  a  little  organ 
called  the  lachrymal  gland,  the  situation  of  which  is  indicated  in 

person  looks  as  much  upward  as  possible,  and  we  shall  see  about  the  whole 
extent  of  the  lower  portion  of  the  conjunctiva,  and  thus,  if  any  foreign  sub- 
stance is  there,  it  will  be  readily  detected,  and  easily  wiped  away  with  a  folded 
soft  rag  or  handkerchief.  Both  lids  have  a  piece  of  cartilage  in  them  to  stiffen 
them,  like  pasteboard,  and  keep  them  fitting  close  to  the  eyeball.  The  upper 
portion  of  this  conjunctival  sac  can  only  be  seen  by  turning  over  the  upper 
lid.  The  way  to  do  this  is  to  let  the  person  look  down  with  the  eyes  closed. 
Taking  hold  of  the  lashes  with  one  hand,  and  applying  a  pencil,  or  some  small, 
round,  smooth  object,  over  the  lid  above  the  globe,  we  lift  the  lashes  out  and 
up,  warning  the  person  to  still  keep  looking  down.  The  lid  will  suddenly 
turn  over  with  a  little  spring  from  the  bending  of  the  cartilage.  In  this  way 
nearly  the  whole  of  the  conjunctival  sac  will  be  exposed,  and  any  foreign 
body  wiped  away,  as  above  described.  But  suppose  no  friend  or  oculist  is  by 
us  to  do  this.  The  next  best  thing  is  to  take  hold  of  the  lashes  of  the  upper 
lid,  and  draw  it  forward  and  downward  over  the  lower  one,  blowing  the  nose 
violently  with  the  other  hand  at  the  same  time. 

"  If  the  foreign  substance  is  on  the  cornea,  take  a  strip  of  paper  not  stiffer 
than  ordinary  writing-paper,  about  a  quarter  of  an  inch  wide,  and  roll  it  up  as 
if  you  were  going  to  make  a  candle-lighter.  Look  at  the  lower  end,  and  you 
will  see  it  comes  to  a  point.  With  this  point  now  you  may  safely  attempt  to 
remove  any  foreign  substance  from  the  corner.  The  tears  which  will  flow 
soften  the  paper,  and  prevent  injury  to  the  delicate  covering  membrane  of  the 
cornea." — Dr.  B.  Jay  Jeffries. 

55.  The  eyelashes?   The  little  points  within  the  line  of  the  lashes?    Of  what  use  ar« 
these  glands? 

56.  The  location  of  the  lachrymal  gland  '    The  use  of  the  gland? 


THE    SPECIAL   SENSES.  245 

Fig.  56,  1.  This  is  the  gland  whence  flows  the  watery  secretion, 
commonly  called  the  tears,  which  is  designed  to  perform  an  exceed- 
ingly important  duty  in  lubricating  the  lids,  and  in  keeping  the  ex- 
posed surface  of  the  eyeball  moist  and  transparent.  For,  without 
this  or  some  similar  liquid,  the  front  of  the  eye  would  speedily 
become  dry  and  lustreless,  like  that  of  a  fish  which  has  been  re- 
moved from  the  water;  the  simple  exposure  of  the  eye  to  the  air 
would  then  suffice  to  destroy  vision. 

57.  This  secretion  of  the  tears  takes  place  at  all  times,  during 
the  night  as  well  as  the  day ;  but  it  is  seldom  noticed,  unless  when 
under  the  influence  of  some  strong  mental  emotion — whether  of  sor- 
row or  happiness — it  is  poured  forth  in  excess,  so  as  to  overflow  the 
lids.     Strong  light  or  a  rapid  breeze  will,  among  many  other  causes, 
excite  the  flow  of  the  tears.     That  portion  of  this  secretion  which 
is  not  used  in  moistening  the  eye  is  carried  off  into  the  nose  by  a 
canal  situated  near  the  inner  angle  of  the  eye,  called  the  nasal  duct. 
This  duct  is  shown  in  Fig.  56,  2,  and  is  connected  with  each  lid  by 
delicate  tubes,  which  are  indicated  by  dotted  lines  in  the  figure ; 
the  asterisk  marks  the  little  opening  in  the  lower  lid,  by  which  the 
tears  enter  the  nasal  duct.     By  gently  turning  the  inner  part  of  that 
lid  downward,  and  looking  in  a  mirror,  this  small  "lachrymal 
point "  may  be  seen  in  your  own  eye.     In  old  people,  these  points 
become  turned  outward,  and  do  not  conduct  the  tears  to  the  nasal 
cavity,  thus  causing  an  overflow  of  tears  upon  the  face. 

58.  Thus  we  observe  that  the  gland  which  forms  the  tears  is 
placed  at  the  outer  part  of  the  eye,  while  their  means  of  exit  is  at 
the  inner  angle  of  the  eye ;  which  fact  renders  it  necessary  that  this 
watery  fluid  shall  pass  over  the  surface  of  the  eyebaH  before  it  can 
escape.     This  arrangement  cannot  be  accidental,  but  evinces  design, 
as  it  thus  secures  the  perfect  lubrication  of  the  surface  of  the  eye, 
and  cleanses  it  from  the  smaller  particles  of  dust  which  may  entei 
it,  in  spite  of  the  vigilance  of  the  lids  and  lashes.     The  act  of 
winking,  which  is  generally  unconsciously  performed,  and  which 
takes  place  six  or  more  times  in  a  minute,  assists  this  passage  of  the 


57.  When  does  the  secretion  of  the  tears  occur?    The  secretion  not  used  for  the  eye! 
Location  of  the  nasai  duct  ?    Its  use  ?    The  overflow  of  tears  in  old  people  ? 

68.  The  watery  fluid  passing  over  the  eyeball  ?    Design  of  the  arrangement?    Winking  I 


246 


THE   SPECIAL   SENSES. 


tears  across  the  eye,  and  is  especially  frequent  when  the  secretion  is 
most  abundant. 

59.  The  Eyeball. — The  eyeball,  or  globe  of  the  eye,  upon  which 
sight  depends,  is,  as  the  name  indicates,  spherical  in  shape.  It  is 
not  a  perfect  sphere,  since  the  front  part  projects  somewhat  beyond 
the  rest,  and  at  the  posterior  part  the  optic  nerve  (Fig.  57,  N)  is 
united  to  it,  resembling  the  junction  of  the  stem  with  the  fruit.  In 


Fia.  57.— VERTICAL  SECTION  OF  THE  EYE.    (Enlarged.) 


C,  The  Cornea. 

A,  The  Aqueous  Humor. 
I,  The  Iris. 

P,  The  Pupil. 

L,  The  Crystalline  Lens. 

H,  The  Ligament  of  the  Lens. 

B,  The  Ciliary  Process. 

V,  The  Cavity  containing  the  Vitreous  Humor. 
S,  The  Sclerotic. 


Ch,  The  Choroid. 

R,  The  Retina. 

N,  The  Optic  Nerve. 

DD,  The  Eyelids. 

X,  The   Levator   Muscle   of   the   Upper 

Lid. 
Y,  The   Upper  Straight  Muscle  of  the 

Eye. 
Z,  The  Lower  Straight  Muscle. 


its  long  diameter — that  is,  from  side  to  side,  it  measures  a  little 
more  than  an  inch ;  in  other  directions  it  is  rather  less  than  an  inch. 
In  structure  the  ball  of  the  eye  is  firm,  and  its  tense  round  contour 
may  in  part  be  felt  by  pressing  the  fingers  over  the  closed  lids. 

60.  The  eyeball  is  composed  chiefly  of  three  internal,  transparent 
media,  called  humors,  and  three  investing  coats,  or  tunics.     The 


59.  Describe  the  shape  of  the  eyeball.    Its  structure. 

60.  Of  what  is  the  eyeball  composed  ?    State  how. 


THE    SPECIAL    SENSES.  247 

former  are  the  aqueous  humor,  Fig.  57,  A,  the  crystalline  lens  L,  and 
the  vitreous  humor  v.  Of  these  the  lens  alone  is  solid.  The  three 
coats  of  the  eyeball  are  called  the  sclerotic  s,  the  choroid  Ch,  and 
the  retina  R.  This  arrangement  exists  in  respect  to  five-sixths  of 
the  globe  of  the  eye,  but  in  the  anterior  one-sixth,  these  coats  are 
replaced  by  the  cornea  c,  which  is  thin  and  transparent,  so  that  the 
rays  of  light  pass  freely  through  it,  as  through  a  clear  window- 
pane. 

61.  In  shape,  the  cornea  is  circular  and  prominent,  resembling  a 
miniature  watch-glass,  about  •£%  of  an  inch  thick.     In  structure, 
it  resembles  horn  (as  the  name  signifies),  or  the  nail  of  the  finger, 
and  is  destitute  of  blood-vessels.     The  sclerotic  (from  scleros,  hard) 
is  composed  of  dense,  white  fibrous  tissue,  and  gives  to  the  eyeball 
its  firmness  of  figure  and  its  white  color ;  in  front,  it  constitutes  the 
part  commonly  called  "the  white  of  the  eye."     It  is  one  of  the 
strongest  tissues  in  the  body.     It  possesses  very  few  vessels,  and 
is  not  very  sensitive.    It  affords  protection  to  the  extremely  delicate 
interior  parts  of  the  eye,  and  the  little  muscles  which  effect  its 
movements  are  inserted  into  the  sclerotic  a  short  distance  behind 
the  cornea  (see  Fig.  57,  Y,  z).     It  is  perforated  posteriorly  to  admit 
the  optic  nerve. 

62.  The  choroid  is  the  second  or  middle  coat  of  the  eyeball,  and 
lies  closely  attached  to  the  inner  surface  of  the  sclerotic.     Unlike 
the  latter,  its  structure  is  soft  and  tender ;  it  is  dark  in  color,  and 
possesses  a  great  abundance  of  blood-vessels.     Its  dark  color  is  due 
to  a  layer  of  dark  brown  or  chocolate-colored  cells  spread  out  over 
its  inner  surface.     This  dark  layer  serves  to  absorb  the  rays  of 
light  after  they  have  traversed  the  transparent  structures  in  front  of 
it.     If  the  rays  were  reflected  from  side  to  side  within  the  eye, 
instead  of  being  thus  absorbed,  confused  vision  would  result  from  the 
multitude  of  images  which  would  be  impressed  upon  the  optic  nerve. 

63.  This  mechanism  has  been   unconsciously  imitated  by  the 
opticians,  who,  when  they  make  a  microscope  or  telescope,  take  care 
that  the  interior  of  its  tube  shall  be  coated  with  a  thick  layer  of 


61.  The  shape  of  the  cornea  ?    Its  structure  ?    The  "  white  of  the  eye  ?  " 

62.  The  second  or  middle  coat  of  the  eyeball  ?    Its  dark  color? 

63.  Similar  mechanism  in  microscopes  ?    The  albinos  ?    White  rabbits  ? 


248 


THE   SPECIAL   SENSES. 


black  paint  or  lamp-black ;  for  without  it,  a  clear  delineation  of  the 

object  to  be  viewed  is  impossible.    The  Albinos,  in  whom  these  dark 

cells  of  the  choroid  are  wanting,  have  imperfect  vision,  especially  in 

^the  daytime  and  in  strong  lights.    The  dark  cells  are  also  wanting  in 

^hite  rabbits,  and  other  animals  that  have  red  or  pink  eyes ;  their 

vision  appears  to  be  imperfect  in  the  presence  of  a  brightlight. 

64.  The  Iris. — Continuous  with  the  choroid,  in  the  front  part  of 
the  globe  of  the  eye,  is  a  thin,  circular  curtain,  which  occasions  the 
brown,  blue,  or  gray  color  of  the  eye  in  different  individuals.  On 
account  of  the  varieties  of  its  color,  this  membrane  has  received  the 

name  7m,  which  is  the  Greek 
word  for  "rainbow"  (see  Fig. 
57,  l).  A  front  view  of  it  is 
shown  in  Fig.  56.  The  iris 
is  pierced  in  its  centre  by  a 
round  opening,  called  the 
pupil  (p),  which  is  constantly 
varying  in  size.  In  olden 
times  it  was  spoken  of  as  the 
"apple  of  the  eye."  The 
hinder  surface  of  the  iris, 
except  in  Albinos,  has  a 
layer  of  dark  coloring  matter 
resembling  that  of  the  cho- 
roid. The  iris  is  a  muscular 
organ,  and  contains  two  dis- 
tinct sets  of  fibres,  one  of  which  is  circular,  while  the  other  radiates 
outward  from  the  pupiL  Their  action  regulates  the  size  of  the 
pupil ;  for  when  the  circular  set  acts,  the  opening  contracts.  Their 
action  is  involuntary,  and  depends  on  the  reflex  system  of  nerves, 
which  causes  the  contraction  of  the  pupil  when  a  strong  light  falls 
upon  the  eye,  and  its  expansion  when  the  illumination  is  feeble.  The 
suspensory  ligament  holds  the  crystalline  lens  in  its  place.  Fig.  58. 
65.  The  iris,  accordingly,  serves  a  very  useful  purpose  in  regulat- 
ing the  admission  of  light  to  the  eye  (see  Fig.  58).  It,  however, 

64.  What  is  the  iris  ?    Its  construction  ?    How  is  the  size  of  the  pupil  regulated  ? 

65.  The  admission  of  light  to  the  eye  ?    The  action  of  the  iris  under  different  circum- 
stances?   The  lustre  of  the  eye.  how  affected  in  vouth  and  old  age  ? 


FIG.  58.— FRONT  SECTION  OF  ITS  EYEBALL, 
VIEWED  FROM  BEHIND,  AND  SHOWING  SUS- 
PENSORY  LIGAMENT,  IRIS,  AND  PUPIL. 


THE   SPECIAL  SENSES.  249 

does  not  act  instantaneously;  and  hence,  when  we  pass  quickly 
from  a  dark  room  into  the  bright  sunlight,  the  vision  is  at  first  con- 
fused by  the  glare  of  light,  but  as  soon  as  the  pupil  contracts,  the 
ability  to  see  becomes  perfect.  On  the  other  hand,  when  we  enter 
a  dark  apartment,  such  as  a  cellar,  for  a  short  time  we  can  see 
nothing  clearly ;  but  as  soon  as  the  pupil  expands  and  admits  more 
light,  we  are  enabled  to  distinguish  the  surrounding  objects.  Ani- 
mals of  the  cat  species,  and  others  which  prowl  around  after  night- 
fall, are  enabled  to  see  in  the  dark  by  having  the  iris  very  dilatable. 
The  size  of  the  pupil  affects  the  lustre  of  the  eye.  When  it  is 
large,  as  it  usually  is  during  youth,  the  eye  appears  clear  and 
brilliant ;  while  in  old  age  the  pupil  is  small  and  the  eye  is  dulL  The 
brilliancy  of  the  eye  is  in  part,  £t,  least,  dependent  upon  the  reflec- 
tion of  light  from  the  front  surface  of  the  crystalline  lens. 

66.  Certain  poisonous  vegetables  have  the  property  of  causing  the 
pupil  to  dilate,  and  have  been  used  in  small  doses  to  increase  the 
beauty  of  the  eye.     One  of  these  drugs  has  been  so  largely  used  by 
the  ladies  for  this  purpose,  that  it  has  received  the  name  belladonna, 
from  the  Italian  words  meaning  "  beautiful  lady."     This  hazardous 
practice  has  resulted  more  than  once  in  the  death  of  the  person 
desiring  thus  to  increase  her  personal  attraction.     The   common 
English  name  for  belladonna  is  "  deadly  nightshade. "     (In  the  dia- 
gram on  page  257  the  shape  and  relations  of  the  iris  are  more  accu- 
rately shown  than  in  the  figure  referred  to  above.) 

67.  The  Retina  constitutes  the  third  and  inner  coat  of  the  globe 
of  the  eye.     This,  the  important  part  of  the  eye  that  is  sensitive  to 
light,  is  a  kind  of  nervous  membrane,  formed  by  the  expansion  of 
the  optic  nerve.     Its  texture  is  soft,  smooth,  and  very  thin ;  it  is 
translucent  and  of  an  opaline,  or  grayish-white  color.     It  is  sensi- 
tive to  light  alone;  and  if  any  form  of  mechanical  irritation  be 
applied  to  it,  the  sensations  of  touch  and  pain  are  not  experienced, 
but  flashes  of  fire,  sparks,  and  other  luminous  appearances  are  per. 
ceived.     Thus  an  electric  shock  given  to  the  eyeball  occasions  a 
flash  of  light ;  and  a  sudden  fall,  or  a  blow  upon  the  eye,  is  often 
apparently  accompanied  by  the  vision  of  "  stars." 

66.  Means  used  to  increase  the  beauty  of  the  eye?    The  injurious  consequences? 

67.  What  part  does  the  retina  constitute?    How  formed?    Its  texture?    Color?    Sensv 
tiveneaa? 


250  THE    SPECIAL   SENSES. 

68.  These  phenomena  are  duo  to  what  is  termed  the  "  specific 
energy  "  of  the  optic  nerve,  which  nerve,  in  common  with  the  other 
nerves  of  the  special  sense,  obeys  a  general  law  of  nature,  which  re- 
quires that,  whenever  one  of  these  nerves  is  stimulated,  it  shall 
respond  with  the  sensation  peculiar  to   itself.      These  flashes  of 
retinal  light  have  no  power  to  illuminate  external  objects,  although 
the  opposite  of  this  statement  has  been  maintained.     On  the  occasion 
of  a  remarkable  trial  in  Germany,  it  was  claimed  by  a  person  who 
had  been  severely  assaulted  on  a  very  dark  night,  that  the  flashes  of 
light  caused  by  repeated  blows  upon  the  head  enabled  him  to  see 
with  sufficient  distinctness   to   recognize   his  assailant.      But  the 
evidence  of   scientific   men    entirely   refuted   this   claim,  by  pro- 
nouncing  that   the   eye,    under    the    circumstances    named,    was 
incapacitated  for  vision.      Too  intense  light  occasions  a  feeling  of 
pain,  but  it  is  of  a  peculiar  kind,  and  is  termed  "  dazzling." 

69.  All  parts  of  the  rethia  are  not  equally  sensitive,  and  sin- 
gularly enough,  the  point  of  entry  of  the  nerve  of  sight  in  the  back 
part  of  the  djj^ball  is  entirely  insensible  to  light,  and  is  called  the 
"  blind  spot."     The  existence  of  this  point  may  be  proved  by  a 
simple  experiment.      Hold  the  accompanying  figure,  on  page  250, 
directly  in  front  of  and  parallel  with  the  eyes.      Close  the  left  eye, 


FIG.  59. 


and  fix  the  sight  steadily  on  the  left-hand  circle  ;  then,  by  gradually 
varying  the  distance  of  the  figure  from  the  eye,  at  a  certain  distance 
(about  six  inches),  the  right-hand  circle  will  disappear,  but  nearer  or 
further  than  that,  it  will  be  plainly  seen.  The  other  eye  may  be 
also  tried,  with  a  similar  result :  if  the  gaze  be  directed  to  the  right- 
hand  circle,  the  left  one  will  seem  to  disappear.  The  experiment 

68.  Specific  energy  of  the  optic  nerve  ?    Trial  in  Germany? 

69.  Sensitiveness  of  all  parts  of  the  retina?    fixpeiuueut  to  pswe  tfce  existence  of  tt»9 
"blind  spot?" 


THE   SPECIAL   SENSES.  251 

may  "be  repeated  by  using  two  black  buttons  on  the  marble  top  of  a 
bureau,  or  on  some  other  white  surface.  The  blind  spot  does  not 
practically  interfere  with  vision,  since  the  eye  is  seldom  fixed 
immovably  on  an  object,  and  the  insensitive  parts  of  the  two  eyes 
can  never  be  directed  upon  the  same  object  at  the  same  time. 

70.  Impressions  made  upon  the  retina  are  not  at  once  lost,  but 
continue  a  measurable  length  of  time,  and  then  gradually  fade  away. 
Thus,  a  bright  light  or  color,  gazed  at  intently,  cannot  be  immedi 
ately  dismissed  from  sight  by  closing  or  turning  away  the  eyes.     A 
stick  lighted  at  one  end,  if  whirled  around  rapidly  in  the  dark,  pre- 
sents the  appearance  of  an  unbroken  luminous  ring ;  and  the  spokes 
of  a  rapidly  revolving  carriage- wheel  seem  to  be  merged  into  a  plane 
surface.      If  an  object  move  too  rapidly  to  produce  this  sort  of 
lasting  impression,  it  is  invisible,  as  in  the  case  of  a  cannon-bal) 
passing  through  the  air  in  front  of  us. 

71.  If  a  card,  painted  with  two  primary  colors — as  red  and  yellow 
— be  made  to  rotate  swiftly,  the  eye  perceives  neither  of  them  dis- 
tinctly  ;  but  the  card  appears  painted  with  their  secondary  color — 
orange.     The  average  duration  of  retinal  images  is  estimated  at  one- 
eighth  of  a  second ;  and  it  is  because  they  thus  endure,  that  the  act 
of  winking,  which  takes  place  so  frequently,  but  so  quickly,  is  not 
noticed  and  does  not  interrupt  the  vision.     The  retina  is  easily 
fatigued  or  deprived  of  its  sensibility.      After  looking  steadfastly 
at  a  bright  light,  or  at  a  white  object  on  a  black  ground,  a  dark  spot, 
corresponding  in   shape   to  the   bright  object,  presents  itself  in 
whatever  direction  we  look.      This  spot  passes  away  as  the  retina 
resumes  its  activity. 

72.  If  a  white  color  be  gazed  at  intently,  and  the  eyes  then  be 
turned  to  a  white  surface,  a  spot  will  appear ;   but  its  color  will  be 
the  complement  of  that  of  the  object.     Fix  the  eye  upon  a  red 
wafer  upon  a  white  ground,  and  on  removing  the  wafer  a  greenish 
spot  of  the  same  shape  takes  its  place.     This  result  happens  because 
a  certain  portion  of  the  retina  has  exhausted  its  power  to  perceive 
the  red  ray,  and  perceives  only  its  complementary  ray,  which  is 

70.  Duration  of  impressions  upon  the  retina?    How  illustrated? 

71.  What  further  illustration?    Winking,  why  it  is  not  noticed?    Ease  with  which  ths 
retina  is  fatigued  or  deprived  of  sensibility  ?    How  shown  ? 

72.  How  further  shown?    How  is  the  result  accounted  for?    "Color-blindness? 


252  THE   SPECIAL   SENSES. 

green.  The  color  thus  substituted  by  the  exhausted  retina  is  called 
a  physiological  or  accidental  color.  In  some  persons  the  retina  is 
incapable  of  distinguishing  different  colors,  when  they  are  said  to 
be  affected  with  "  color-blindness."  Thus,  red  and  green  may  ap- 
pear alike,  and  then  a  cherry-tree,  full  of  ripe  fruit,  will  seem  of  the 
same  color  in  every  part.  Railroad  accidents  have  occurred  because 
the  engineer  of  the  train,  who  was  color-blind,  has  mistaken  the 
color  of  a  signal.  (Read  Note  9. ) 

73.  The  Crystalline  Lens. — Across  the  front  of  the  eye,  just 
behind  the  iris,  is  situated  the  crystalline  lens,  enclosed  within  its 
own  capsule.     It  is  supported  in  its  place  partly  by  a  delicate  circu- 
lar ligament,  and  partly  by  the  pressure  of  adjacent  structures.     It 
is  colorless  and  perfectly  transparent,  and  has  a  firm  but  elastic 
texture.     In  shape,  it  is  doubly  convex,  and  may  be  rudely  com- 
pared to  a  small  lemon-drop.     The  front  face  of  the  lens  is  natter 
than  the  other,  and  is  in  contact  with  the  iris  near  its  pupillary 
margin,  as  is  represented  in  the  diagram  on  page  257.     It  is  only 
one-fourth  of  an  inch  thick. 

74.  When  this  little  body  becomes  opaque,  and  no  longer  affords 
free  passage  to  the  rays  of  light,  as  often  happens  with  the  advance 
of  age,  an  affection  termed  "  cataract "  is  produced.     Between  the 
crystalline  lens  and  the  cornea  is  a  small  space  which  contains  the 

9.  Color-blindness. — "  Daltonism,  or  color-blindness,  receives  its  name 
from  the  eminent  English  chemist,  who  described  this  infirmity  as  it  existed 
in  his  own  case.  It  arises  from  an  unnatural  condition  of  the  organs  of  vision 
which  prevents  the  discrimination  of  certain  colors.  Some  persons  will  mis- 
take red  for  green  ;  so  that  ripe  cherries  on  a  tree  appear  the  same  as  the 
leaves ;  others  recognize  only  black  and  white.  Persons  thus  affected  are 
sometimes  incapable  of  discriminating  musical  tones.  The  healthy  eye  ordi- 
narily fails  to  discriminate  between  certain  colors,  blue  and  green  especially, 
when  viewed  by  artificial  light.  But  even  this  may  in  a  measure  be  overcome 
by  training,  so  that  an  expert  dealer  in  silk  obtains  a  knowledge  of  the  shades 
of  blue,  green,  and  violet,  which  is  proof  against  the  confusing  influence  of  gas- 
light and  tinted  curtains.  The  eyes  of  persons  who  have  much  to  do  with 
colors  are  more  liable  to  become  overstrained  than  those  dealing  chiefly  with 
rays  of  white  light. " — Flint's  Physiology  (in  part). 


73."   The  location  of  the  crystalline  lens?    How  supported?    Its    color  and  texture! 
Shape?    Size? 

74.  Cataract  ?    Aqueous  humor  ?    Vitreous  humor  ? 


THE   SPECIAL  SENSES.  253 

aqueous  humor  (see  Fig.  57,  A).  This  humor  consists  of  five  or  six 
drops  of  a  clear,  colorless  liquid  very  much  like  water,  as  its  name 
implies.  That  part  of  the  globe  of  the  eye  lying  behind  the  lens  is 
occupied  by  the  vitreous  humor,  so  called  from  its  fancied  resem- 
blance to  melted  glass  (Fig.  57,  v).  This  humor  is  a  transparent, 
jelly-like  mass,  enclosed  within  an  exceedingly  thin  membrane.  It 
lies  very  closely  applied  to  the  retina,  or  nervous  membrane  of  the 
eye,  and  constitutes  fully  two-thirds  of  the  bulk  of  the  eyebalL 

75.  The  Uses  of  the  Crystalline  Lens. — A  convex  lens  has 
the  property  of  converging  the  rays  of  light  which  pass  through  it ; 
and  the  point  at  which  it  causes  them  to  meet  is  termed  its  focus. 


FIG.  60.— THE  RETINAL  IMAGE. 

If  a  lens  of  this  description,  such  as  a  magnifying  or  burning-glass, 
be  held  in  front  of  an  open  window,  in  such  a  position  as  to  allow 
its  focus  to  fall  upon  a  piece  of  paper,  it  will  be  found  to  depict 
upon  the  paper  a  miniature  image  of  the  scene  outside  of  the  win- 
dow. It  will  be  further  noticed  that  the  image  is  inverted,  or  up- 
side down,  and  that  the  paper  at  the  place  upon  which  the  image  is 
thrown  is  much  brighter  than  any  other  part. 

76.  Now  all  the  transparent  structures  of  the  eye,  but  especially 
the  crystalline  lens,  operate  upon  the  retina,  as  the  convex  lens  acts 
upon  the  paper — that  is,  they  paint  upon  the  retina  a  bright,  in- 
verted miniature  of  the  objects  that  appear  in  front  of  the  eye 
(Fig.  60).  That  this  actually  takes  place  may  be  proved  by  experi- 
ment. If  the  eyeball  of  a  white  rabbit,  the  walls  of  which  are 

75.  \fihat  is  a  lens  and  its  focus  ?    The  miniature  image,  how  produced  ? 

76.  How  are  iiyures  painted  upon  the  retina  ?    Ilow  proved  ? 


254  '.HE    SPECIAL   SENSES. 

transparent,  be  examined  while  a  lighted  candle  is  held  before  the 
cornea,  an  image  of  the  candle-flame  may  be  seen  Tipon  the  retina. 

77.  The  form  and  structure  of  the  crystalline  lens  endow  it  with 
a  remarkable  degree  of  refractive  power,  and  enable  it  to  converge 
all  the  rays  of  light  that  enter  it  through  the  pupil,  to  a  focus 
exactly  at  the  surface  of  the  retina.     When  this  lens  is  removed 
from  the  eye,  as  is  frequently  done  for  the  cure  of  cataract,  it  is 
found  that  the  rays  of  light  then  have  their  focus  three-eighths  of 
an  inch  behind  the  retina ;  that  the  image  is  four  times  larger  than 
in  the  healthy  eye;  that  it  is  less  brilliant,  and  that  its  outline  is 
very  indistinct.     From  this  we  learn  that  one  of  the  uses  of  the 
crystalline  lens  is  to  make  the  retinal  image  bright  and  sharply- 
defined,  at  the  same  time  that  it  reduces  its  size.     Indeed,  the  small 
size  of  the  image  is  a  great  advantage,  as  it  enables  the  limited  sur- 
face of  the  retina  to  receive,  at  a  glance,  impressions  from  a  con- 
siderable field  of  vision. 

78.  As  the  image  upon  the  retina  is  inverted,  how  does  the 
mind  perceive  the  object  in  its  true,  erect  position  ?     Many  expla- 
nations have  been  advanced,  but  the  simplest  and  most  satisfactory 
appears  to  be  found  in  the  fact  that  the  retina  observes  n'o  differ- 
ence, so  to  speak,  between  the  right  and  left  or  the  upper  and  lower 
positions  of  objects.     In  fact,  the  mind  is  never  conscious  of  the 
formation  of  a  retinal  image,  and  until  instructed,  has  no  knowledge 
that  it  exists.     Consequently,  our  knowledge  of  the  relative  loca- 
tion of  external  objects  must  be  obtained  from  some  other  source 
than  the  retina.     The  probable  source  of  this  knowledge  is  the 
habitual  comparison  of  those  objects  with  the  position  of  our  own 
bodies ;  thus,  to  see  an  elevated  object,  we  know  we  must  raise  the 
head  and  eyes ;  and  to  see  one  at  our  right  hand,  we  must  turn  the 
head  and  eyes  to  the  right. 

79.  Long-sight  or  Hyperopia,  and  Short-sight  or  Myopia.— 
The  eye  is  not  in  all  cases  perfectly  formed.     For  example,  persons 
may  from  birth  have  the  cornea  too  prominent  or  too  flat,  or  the 
lens  may  be  too  thick  or  too  thin.     In  either  of  these  conditions 
sight  will  be  more  or  less  defective  from  the  first,  and  the  defect 

77.  What  can  be  said  in  respect  to  the  form  and  structure  of  the  crystalline  lens  ? 

78.  How  is  the  inverted  image  upon  the  retina  presented  in  its  true  position  to  the  mind? 

79.  The  uniform  perfection  of  the  eye  ?    Examples  ?    The  most  common  imperfection  ? 


THE   SPECIAL   SENSES.  255 

will  not  tend  to  disappear  as  life  advances.  The  most  common 
imperfection,  however,  is  in  the  shape  of  the  globe ;  which  may  be 
short  (Fig.  61,  H),  as  compared  with  the  natural  eye,  N,  or  it  may 
be  too  long,  M. 

80.  When  the  globe  is  short,  only  objects  that  are  at  a  distance 
can  be  clearly  seen,  and  the  condition  of  the  vision  is  known  as 
"  long-sight,"  or  hyperopia.  It  will  be  observed,  by  reference  to 
Fig.  61,  that  the  focus  of  the  rays  of  light  would  fall  behind  the 
retina  of  this  eye.  When  the  globe  is  too  long,  only  objects  that 


FIG.  61.— THE  DIFFERENT  SHAPES  OF  THE  GLOBE  OF  THE  EYE. 

N,  The  Natural  Eye.  M,  The  Short-sighted  Eye. 

H,  The  Long-sighted  Eye.  S,  Parallel  Rays  from  the  Sun. 

are  very  near  to  the  eye  can  be  clearly  seen,  and  the  condition 
resulting  from  this  defect  is  termed  "  short-sight,"  or  myopia.  The 
focus  of  the  rays  of  light  is,  in  this  case,  formed  in  the  interior  of 
the  eye  in  front  of  the  retina. 

81.  Long-sight,  or  hyperopia^Js  common  among  school-children, 
nearly  as  much  so  as  short-sight,  and  must  not  be  confounded  with 
the  defect  known  as  the  "  far  sight "  of  old  people ;  although  in  both 
affections  the  sight  is  improved  by  the  jise  of  convex  glasses, 
Children  not  infrequently  discover  that  they  see  much  better  when 
they  chance  to  put  on  the  spectacles  of  old  persons.  For  the  relief 
of  short-sight,  concave  glasses  should  be  employed ;  as  they  so 
scatter  the  rays  of  light  as  to  bring  the  focus  to  the  retina,  and  thus 
cause  the  vision  of  remote  objects  to  become  at  once  distinct.  That 
form  of  "  squint,"  in  which  the  eyes  are  turned  inward,  is  generally 

80.  How  is  " long-sfeht*  explained?    "Short-sight?" 

81.  Long-sight,  how  common  ?    With  what  must  it  not  tw  confounded  ?     Kind  of  glasses 
for  short-sight?    Why?    Squint? 


256  THE   SPECIAL   SENSES. 

dependent  upon  long-sight,  while  that  rarer  form,  when  they  turn 
outward,  is  due  to  short-sight.    (Read  Note  10.) 

82.  The    Function   of  Accommodation. — If,  after  looking 
through  an  opera-glass  at  a  very  distant  object,  it  is  desired  to  view 
another  nearer  at  hand,  it  will  be  found  impossible  to  obtain  a  clear 
vision  of  the  second  object  unless  the  adjustment  of  the  instrument 
be  altered,  which  is  effected  by  means  of  the  screw.     If  an  object, 
like  the  end  of  a  pencil,  be  held  near  the  eye,  in  a  line  with  another 
object  at  the  other  side  of  the  room,  or  out  of  the  window,  and  the 
eye  be  fixed  first  upon  one  and  then  upon  the  other,  it  will  be  found 
that  when  the  pencil  is  clearly  seen,  the  further  object  is  indistinct ; 
and  when  the  latter  is  seen  clearly,  the  pencil  appears  indistinct,  and 
that  it  is  impossible  to  see  both  clearly  at  the  same  time.      Accord- 
ingly, the  eye  must  have  the  capacity  of  adjusting  itself  to  distances, 
which  is  in  some  manner  comparable  to  the  action  of  the  screw  of 
the  opera-glass^ 

83.  This,  which  has  been  called  the  function  of  accommodation, 
is  one  of  the  most  admirable  of  all  the  powers  of  the  eye,  and  is 
exercised  by  the  crystalline  lens.     It  consists  essentially  in  a  change 
in  the  curvature  of  the  front  surface  of  the  lens,  partly  through  its 

10.  On  the  Production  of  Short-Sight. — "  The  observations  of  Cohn 
in  the  schools  and  University  of  Breslau,  of  Kruger  in  Frankfort-on-the-Main, 
of  Erismann  in  St.  Petersburgh,  of  Von  Hoffmann  in  "Wiesbaden,  and  others 
abroad,  prove  most  conclusively  that  one  of  the  bad  effects  of  school  and  college 
life  is  to  produce  diseases  of  the  eyes.  They  have  shown  that  near-sightedness 
increases  rapidly  in  frequency  as  you  go  up  in  the  scale  of  schools  from  the 
primaries  of  the  rural  districts  to  the  universities.  The  gravity  of  this  finding 
may  be  appreciated  when  we  remember  that  near-sightedness  is  a  disease,  and 
that  it  very  frequently  descends  from  one  generation  to  another,  marked  by 
such  organic  changes  in  the  eyes  as  tend  to  the  production  of  the  worst  forms 
of  the  malady,  and  to  blindness.  In  1867,  Cohn,  of  Breslau,  published  the 
results  of  the  examination  of  the  eyes  of  10,060  scholars.  His  examinations 
covered  the  entire  range  of  school-life.  He  found  that  1,750  of  the  10,060 
children  had  defective  vision — about  seventeen  per  cent.  He  also  examined, 
without  selection,  410  of  the  964  students  of  the  Breslau  University,  and  found 
that  not  one-third  had  normal  eyes." — Dr.  C.  R.  Agnew. 


82.  What  is  stated  in  connection  with  the  opera-glass  ?  Experiment  with  pencil  and  dis. 
tant  object? 

83.  Function  of  accommodation?     In  what  does  it  consist?     How  is  the  function 
explained? 


THE    SPECIAL   SEN3B8.  257 

own  elasticity,  and  partly  through  the  action  of  the  ciliary  muscle. 
When  the  eye  is  at  rest — that  is,  when  accommodated  for  a  distant 
Object — the  lens  is  natter  and  its  curvature  diminished  (see  Fig.  62)  ; 
but  when  strongly  accommodated  for  near  vision,  the  lens  becomes 
thicker,  its  curvature  increases,  and  the  image  on  the  retina  is  made 
more  sharp  and  distinct.  Since  a  strong  light  is  not  required  in 


VIQ.  62.— THE  FUNCTION  OF  ACCOMMODATION. 

The  right  half  of  the  diagram  shows  the  eye  at  rest.    The  left  half  shows  the  lens 
accommodated  for  near  vision. 

viewing  near  objects,  the  pupil  contracts,  as  is  shown  in  the  left- 
hand  half  of  the  diagram. 

84.  Old-sight,  OP  Presbyopia. — But  this  marvelously  beautiful 
mechanism  becomes  worn  with  use;  or,  more  strictly  speaking,  tho 
lens,  like  other  structures  of  the  body,  becomes  harder  with  the  ap-_ 
proach  of  old  age.  The  material  composing  the  lens  becomes  less 
elastic,  the  power  to  increase  its  curvature  is  gradually  lost,  and  as  a 
consequence,  the  person  is  obliged  to  hold  the  book  further  away 
when  reading,  and  to  seek  a  stronger  light.  In  a  word,  the  function 
of  accommodation  begins  to  fail,  and  is  about  the  first  evidence  that 
marks  the  decline  of  life.  By  looking  at  the  last  preceding  dia- 
gram, and  remembering  that  the  increased  curvature  of  the  lens 
cannot  take  place,  it  will  be  at  once  understood  why  old-sight  is 
benefited  in  near  vision  by  the  eonvex  lens,  such  as  the  spectacles 
of  old  people  contain.  It  acts  as  a  substitute  for  the  deficiency  of 
the  crystalline  lens.  (Read  Note  u.) 

11.  The  Choice  of  Glasses. — "The  perfectly  healthy,   normal  eye, 
begins  to  need  a  glass  for  ordinary  work  at  between  forty  and  forty-five  years 

84.  Change  of  sight  with  the  approach  of  old  age  ?    Explain  the  chance  ? 


25&-     }•  THE    SPECIAL   SENSES. 

85.  The  Sense  of  Hearing — Sound. — Hearing  is  the  special 
<W"    sense  by  means  of  which  we    are    made   acquainted  with  sound. 

x  "What  is  sound  1  It  is  an  impression  made  upon  the  organs  of  hear- 
ing, by  the  vibrations  of  elastic  bodies.  This  impression  is  com- 
monly propagated  by  means  of  the  air,  which  is  thrown  into 
delicate  undulations  in  all  directions  from  the  vibrating  substance. 
When  a  stone  is  thrown  into  smooth  water,  a  wave  of  circular  form 
is  set  in  motion  from  the  point  where  the  stone  struck,  which,  as  it 
advances,  constantly  increases  in  size  and  diminishes  in  force. 

86.  Somewhat  resembling  this  is  the  undulation,  or  sound-wave, 

of  age — of  course,  we  here  exclude  all  debilitated  conditions  of  the  body  result- 
ing from  disease.  Now,  then,  comes  the  question — shall  we  put  on  glasses, 
and  of  what  strength  ?  To  answer  some  prevalent  fallacies  handed  down  from 
one  generation  to  another,  we  cannot  do  better  than  quote  from  the  highest 
authority  >  Prof.  Bonders,  who  says :  '  The  opinion  is  rather  general  that  we 
should  refrain  as  long  as  possible  from  the  use  of  convex  glasses.  But,  is  it 
not  folly  to  weary  the  eyes  and  the  mind  together,  without  necessarily  con- 
demning ourselves  to  guess,  with  much  trouble,  at  the  forms  which  we  could 
see  pretty  well  with  glasses  ?' 

"  Strangely  enough,  people  have  fallen  also  into  the  opposite  fault  Some 
have  thought,  by  the  early  use  of  spectacles,  to  be  able  to  preserve  their  power 
of  vision,  and  have  recommended  and  employed  *  conservative  glasses. '  If  I 
am  not  mistaken,  self-interest  had  something  to  do  with  this  recommendation. 
So  long  as  the  eye  does  not  err,  and  remains  free  from  fatigue  in  the  work  re- 
quired of  it,  its  own  power  is  sufficient,  and  it  is  inexpedient  to  seek  assistance 
in  the  use'of  convex  glasses.  Having  made  up  their  minds  that  they  require 
glasses,  how  are  they  to  know  what  glasses  to  procure,  or  what  number  is  cor- 
rect ?  Generally,  people  go  to  the  nearest  spectacle- vender,  and  purchase  what 
they  see  best  with  at  the  time.  We  say  distinctly,  once  lor  all,  that  the 
ophthalmic  surgeon  is  the  one  to  be  consulted  as  to  the  wearing  of  glasses. 
He,  by  testing  the  eye,  can  alone  decide  whether  any,  and  what  glasses,  should 
be  worn.  Opticians  and  spectacle- venders  know  nothing  about  the  laws  which 
govern  the  refraction  and  accommodation  of  the  eye.  It  is  not  their  business, 
any  more  than  it  is  the  apothecary's  to  know  about  disease.  The  advice  of  the 
ophthalmic  surgeon  will  also  be  found  invaluable  as  to  how  to  wear  glasses, 
whether  springs  or  spectacles,  so  as  not  to  fatigue  the  eyes  by  straining  them 
from  improper  use  of  these  invaluable  aids  to  man's  happiness.  We  conclude 
by  saying,  that  all  advice  in  this  article  applies  to  those  having  normal, 
healthy,  strong  eyes." — Dr.  B.  Joy  Jeffries. 


85.  Hearing?    What  ia  sound  ?    How  propagated  commonly  ?    Stone  thrown  in  water? 

86.  Sound-wave  in  the  atmosphere  ?    Its  shape?    Bate  of  motion?    Sound,  in  water,  a 
and  solid  bodies? 


THE   SPECIAL   SENSES.  259 

which  is  imparted  by  a  sonorous  vibration  to  the  surrounding 
atmosphere.  Its  shape,  however,  is  spherical,  rather  than  circular, 
since  it  radiates  upward,  downward,  and  obliquely,  as  well  as  hori- 
zontally, like  the  wave  in  water.  The  rate  of  motion  of  this 
spherical  wave  of  air  is  about  1,050  feet  per  second,  or  one  mile  in 
five  seconds.  In-  water,  sound  travels  four  times  as  fast  as  in  air, 
and  still  more  rapidly  through  solid  bodies ;  along  an  iron  rod  its 
velocity  is  equal  to  two  miles  per  second. 

87.  The  earth,  likewise,  is  a  good  conductor  of  sound.     It  is  said 
that  the  Indian  of  our  western  prairies  can,  by  listening  at  the  sur- 
face of  the  ground,  hear  the  advance  of  a  troop  of  cavalry  while 
they  are  still  out  of  sight,  and  can  even  discriminate  between  their 
tread  and  that  of  a  herd  of  buffaloes.     Solid  substances  also  convey 
sounds  with  greater  power  than  air.     If  the  ear  be  pressed  against 
one  end  of  a  long  beam,  the  scratching  of  a  pin  at  the  other 
extremity  may  be  distinctly  heard,  which  will  not  be  at  all  audible 
when  the  ear  is  removed  from  the  beam.     Although  air  is  not  the 
best  medium  for  conveying  sound,  it  is  necessary  for  its  production. 
Sound  cannot  be  produced  in  a  vacuum,  as  is  shown  by  ringing  a 
bell  in  the  exhausted  receiver  of  an  air-pump,  for  it  is  then  entirely 
inaudible.     But  let  the  air  be  re-admitted  gradually,  then  the  tones 
become  more  and  more  distinct,  and  when  the  receiver  is  again  full 
of  air,  they  will  be  as  clear  as  usual. 

88.  All  sonorous  bodies  do  not  vibrate  with  the  same  degree  of 
rapidity,  and  upon  this  fact  depends  the  pitch  of  the  sounds  that 
they  respectively   produce.     The   more  frequent  the  number  of 
vibrations  within  a  given  time,  the  higher  will  be  the  pitch ;  and 
the  fewer  their  number,  the  lower  or  graver  will  it  be.     Now,  the 
rate  of  the  successive  vibrations  of  different  notes  has  been  meas- 
ured, and  it  has  thus  been  found  that  if  they  are  less  than  sixteen 
in  a  second,  no  sound  is  audible;  while,  if  they  exceed  60,000  pet 
second,  the  sound  is  very  faint,  and  is  painful  to  the  ear.     The  ex- 
treme limit  of  the  capacity  of  the  human  ear  may  be  considered  as 
included  between  these  points,  but  the  sounds  which  we  ordinarily 
hear  are  embraced  between  7  00  and  3,000  vibrations  per  second. 

87.  The  earth  as  a  conductor  of  sound?    What  has  the  western  Indian  been  taught? 
Solid  substances  as  conductors  ?  As  regards  sound,  in  what  respect  is  air  necessary?  Sound 
in  a  vacuum  ? 

88.  Pitch,    To  what  due?    Capacity  of  ear? 


260 


THE    SPECIAL    SENSES. 


89.  The  ear,  winch  is  the  proper  organ  of  hearing,  is  the  most 
complicated  of  all  the  structures  that  are  employed  in  the  reception 
of  external  impressions.  The  parts  of  which  it  is  composed  are 
numerous,  and  some  of  them  are  extremely  small  and  delicate. 
Nearly  all  these  parts  are  located  in  an  irregularly  shaped  cavity 
hollowed  out  in  the  temporal,  or  "  temple  "  bone  of  each  side  of  the 
head.  That  part  of  the  bone  in  which  the  auditory  cavity  is  placed 
has  the  densest  structure  of  all  bones  of  the  body,  and  has,  there- 
fore, been  called  the  "  petrous,"  or  rocky  part  of  the  temporal  bone. 
In  studying  the  ear,  it  is  necessary  to  consider  it  as  divided  into 


Fio.  63.— THE  EAR  AND  ITS  DIFFERENT  PARTS. 

A,  Diagram  of  the  Ear. 

a,  6,  External  Ear.  d,  Middle  Ear. 

c,  Membrana  tympani.  e,  Internal  Ear. 

B  to  B'",  Bones  of  the  Middle  Ear  (magnified). 
C,  The  Labyrinths,  or  Internal  Ear  (highly  magnified). 

three  portions,  which  are  called,  from  their  relative  positions,  the 
external  ear,  the  middle  ear,  and  the  internal  ear.  (In  the  diagram, 
Fig.  B3,  A,  the  first  is  not  shaded,  the  second  is  lightly  shaded,  and 
"la§t  has  a  dark  background.) 

90.  The  External  Ear. — The  external  portion  of  the  organ  of 
hearing,  designated  in  Fig.  63,  A,  includes,  first,  that  outer  part 
'(a),  which  is  commonly  spoken  of  as  "  the  ear,"  but  which  in  fact 

89.  The  ear.     Its  divisions. 

90.  Of  what  does  the  external  portion  of  the  organ  of  hearing  consist?    Describe  th« 
portal  of  that  organ  known  as  the  ear.    Its  use  ? 


THE   SPECIAL   SENSES.  261 

is  only  the  portal  of  that  organ ;  and,  secondly,  the  auditory  canal 
(b).  The  former  consists  of  a  flat,  flexible  piece  of  cartilage,  pro- 
jecting slightly  from  the  side  of  the  head,  attached  to  it  by  liga- 
ments, and  supplied  with  a  few  weak  muscles.  Its  surface  is 
uneven,  and  curiously  curved,  and  from  its  resemblance  to  a  shell, 
it  has  been  called  the  concha.  It  probably  serves  to  collect  sounds} 
and  to  give  them  an  inward  direction,  although  its  removal  is  said 
not  to  impair  the  acuteness  of  hearing  more  than  a  few  days. 

91.  In  those  animals  whose  hearing  is  more  delicate  than  that  of 
man,  the  corresponding  organ  is  of  greater  importance,  it  being 
larger,  and  supplied  with  muscles  of  greater  power,  so  that  it  serves 
as  a  natural  kind  of  ear-trumpet,  which  is  easily  movable  in  the 
direction  of  any  sound  that  attracts  the  attention  of  the  animal 
Bold,  preying  animals  generally  have  the  concavity  of  this  organ 
directed  forward,  while  in  timorous  animals,  like  the  rabbit,  it  is 
directed  backward.     Fishes  have  no  outer  ear,  but  sounds  are  trans- 
mitted directly  through  the  solid  bones  of  the  head,  to  the  internal 
organ  of  hearing. 

92.  The  auditory  canal  (Fig.  63,  A,  b),  which  is  continuous  with 
the  outer  opening  of  the  ear,  is  a  passage  an  inch  and  a  quarter  in 
length,  its  inner  extremity  being  bounded  by  a  closely-fitting,  cir- 
cular membrane.     This  canal  is  of  oval  form,  is  directed  forward 
and  inward,  and  is  slightly  curved,  so  that  the  inner  end  is  ordi- 
narily concealed  from  view.    The  pouch  of  the  skin  which  lines  this 
passage  is  smooth  and  thin,  especially  at  the  lower  end,  where  it 
covers  the  membrane  just  mentioned. 

93.  As  in  the  case  of  the  nostrils,  a  number  of  small,  stiff  hairs 
garnish  the  margin  of  the  auditory  canal,  and  guard  it,  to  some 
extent,  against  the  entrance  of  insects  and  other  foreign  objects 
The  skin,  too,  covering  its  outer  half,  is  furnished  with  a  belt  of 
little  glands  which  secrete  a  yellow,  bitter  substance,  called  "  ear- 
wax,"  which  is  especially  obnoxious  to  small  insects.     As  the  outer 
layer  of  this  wax-like  material  loses  its  useful  properties  it  becomes 
dry,  and  falls  out  of  the  ear  in  the  form  of  minute,  thin  scales,  a 
fresh  supply  being  furnished  from  the  little  glands  beneath.     In  its 

91.  The  ear  in  the  animals  of  delicate  hearing?    Rabbit?    Fishes! 

92.  What  is  the  auditory  canal  T    Describe  it  f 

93.  How  is  it  guarded  aud  protected?    Ear-wax? 


262 


THE   SPECIAL   SENSES. 


form,  the  auditory  canal  resembles  the  tube  of  an  ear-trumpet,  and 
serves  to  convey  the  waves  of  sound  to  the  middle  portion  of  the 
ear. 

94.  The  Middle  Ear,  OP  Tympanum. — The  middle  ear  is  a 
small  cavity,  or  chamber,  of  irregular  shape,  about  one-fourth  of  an 
inch  across  from  side  to  side,  and  half  an  inch  long  (see  Fig.  63, 
A,  d).  From  the  peculiar  arrangment  of  its  various  parts  it  has 


Pio.  64.— SHOWING  THE  INTERNAL  MECHANISM  OF  THE  EAR  (GREATLY  ENLARGED), 

very  properly  been  called  the  tympanum,  or  the  "  drum  of  the  ear.  " 
The  middle  ear,  like  the  external  canal,  contains  air. 

95.  The  circular  membrane,  already  mentioned  as  closing  the 
auditory  canal,  is  the  partition  which  separates  the  middle  from  the 
external  ear,  and  is  called  the  membrana  tympani  (c),  and  may  be 
considered  as  the  outer  head  of  the  drum  of  the  ear.  It  is  some- 
times itself  spoken  of  as  the  "  drum,"  but  this  is  incorrect,  since  a 
drum  is  not  a  membrane,  but  is  the  hollow  space  across  which  the 
membrane  is  stretched.  This  membranous  drum-head  is  very  tense 
and  elastic,  and  so  thin  as  to  be  almost  transparent ;  its  margin  is 
fastened  into  a  circular  groove  in  the  adjacent  bone.  Each  wave  of 


94.  What  is  the  middle  ear?    Why  called  tympanum  f 
05.  What  is  the  membrana  tympani  ?    Describe  it- 


THE    SPECIAL   SENSES.  263 

sound  that  touches  this   delicate  membrane  causes  it  to  vibrate, 
and  it,  in  turn,  excites  movements  in  the  parts  beyond. 

96.  Within  the  tympanum  is  arranged  a  chain  of  remarkable 
"  little  bones,"  or  ossicles.     They  are  chiefly  three  in  number,  and 
from  their  peculiar  shapes  bear  the  following  names :  malleus,  or 
the  mallet;  incus,  or  the  anvil;  and  stapes,  or  the  stirrup.    A  fourth, 
the  smallest  bone  in  the  body,  in  early  life  intervenes  between  the 
incus  and  stapes,  but  at  a  later  period  it  becomes  a  part  of  the 
incus.     It  is  called  the  orbicular  bone.     Small  as  are  these  ossicles 
— and  they,  together,  weigh  only  a  few  grains — they  have  their 
little  muscles,  cartilages,  and  blood-vessels,  as  perfectly  arranged  as 
the  larger  bones  of  the  body.     One  end  of  the  chain  of  ossicles,  the 
mallet,  is  attached  to  the  membrane  of  the  tympanum,  or  outer 
drum-head,  while  the  other  end,  the  stirrup,  is  firmly  joined  by  its 
foot-piece  to  a  membrane  in  the  opposite  side  of  the  cavity.     The 
chain,  accordingly,  hangs  suspended  across  the  drum  between  the 
two  membranes;  and  when  the  outer  one  vibrates  under  the  influ- 
ence of  the  sound-wave,  the  chain  swings  inward  and  transmits  the 
vibration  to  the  entrance  of  the  inner  ear. 

97.  The  musical  instrument,  the  drum,  is  not  complete  if  the 
air  within  be  perfectly  confined ;  we  therefore  find  in  all  instru- 
ments of  this  kind  a  small  opening  in  the  side,  through  which  air 
may  pass  freely.     By  this  means  the  pressure  of  the  air  upon  the 
vellum  which  forms  the  head  of  the  drum  is  made  equal  upon  all 
sides,  and  the  resonance  of  the  drum  remains  unaffected  by  the 
varying  density  of   the  atmosphere.     It  will,  therefore,  emit  its 
proper  sound,  whether  it  be  struck   in  the  rarefied   air  of  the 
mountain-top,  or  in  the  condensed  air  of  a  mine.     The  tympanum, 
or  drum  of  the  ear,  in  like  manner  has  an  opening,  by  means  of 
•which  it  communicates  freely  with  the  external  air.     This  opening 
is  a  narrow  canal,  about  an   inch  and  a  half  long,  called   the 
Eustachian  tube,  after  the  name  of  its  discoverer,  Eustachius. 

98.  The  course  of  this  passage  is  indicated  in  Fig.  64,  directed 
downward  and  inward :    its  other  extremity  opens  into  the  upper 


96.  What  are  the  ossicles  ?    Their  number  and  names  ?    Their  arrangement  ? 

97.  The  Eustachian  tube  ?    Describe  it,  and  state  its  use. 

98.  What  can  you  state  of  the  action  of  the  Eustachian  tube  2 


264 


THE    SPECIAL   SENSES. 


part  of  the  throat.  The  passage  itself  is  ordinarily  closed,  but 
whenever  the  act  of  swallowing  or  gaping  takes  place,  the  orifice  in 
the  throat  is  stretched  open,  and  the  air  of  the  cavity  of  the 
tympanum  may  then  be  renewed.  Air  may  at  will  be  made  to  enter 
through  this  tube,  by  closing  the  mouth  and  nose,  and  then  trying 


Fio.  65.— SECTION  OF  THE  RIGHT  EAR. 


A,  The  Concha. 

B,  Auditory  Canal. 

C,  Membrane  of  the  Drum. 

(the  lower  half.) 

D,  A  Small  Muscle. 


E,  Incus,  or  Anvil. 

M,  Malleus,  or  Mallet 

I,  Eustachian  Tube. 

G,  Semicircular  Canals. 

H,  Cochlea,  or  Snail's  ShelL 


to  force  air  through  the  latter.  When  this  is  done,  a  distinct 
crackle  or  clicking  sound  is  perceived,  due  to  the  movement  of  the 
membranes,  and  of  the  little  bones  of  the  ear. 

99.  The  Eustachian  tube  serves,  also,  as  an  escape-pipe  for  the 
fluids  which  form  within  the  middle  ear ;  and  hence,  when  its  lining 
membrane  becomes  thickened,  in  consequence  of  a  cold  or  sore 
throat,  and  the  passage  is  thus  more  or  less  choked  up,  the  fluids 
are  unable  to  escape  as  usual,  and  therefore  accumulate  within  the 


99.  What  other  purpose  does  the  Eustachian  tube  serve?  How  is  this  shown? 
Primary  use  of  the  Eustachian  tube  ? 


"Throat- 


THE    SPECIAL    SENSES.  265 

ear.  When  this  takes  place,  the  vibrations  of  the  membrane  are 
interfered  with  ;  the  sounds  heard  appear  muffled  and  indistinct ; 
and  a  temporary  difficulty  of  hearing,  which  is  known  as  "  throat- 
deafness,"  is  the  result.  This  result  resembles  the  effect  produced 
by  interrupting  the  vibrations  of  a  sonorous  body,  such  as  all  are 
familiar  with ;  if  the  finger  be  placed  upon  a  piano-string  or  bell 
when  it  is  struck,  the  proper  sound  is  no  longer  fully  and  clearly 
emitted.  But  the  primary  use  of  this  tube  is  to  afford  a  free  com- 
munication  between  the  middle  ear  and  the  external  atmosphere, 
and  thus  secure  an  equal  pressure  upon  both  sides  of  the  membrane 
of  the  drum  of  the  ear,  however  the  density  of  the  atmosphere  may 
vary.  If,  from  undue  tension  of  the  membrane,  pain  is  experienced 
in  the  ears,  when  ascending  into  a  rare  atmosphere,  as  in  a  balloon, 
or  descending  into  a  dense  one,  as  in  a  diving-bell,  it  may  be 
relieved  by  repeating  the  act  of  swallowing,  from  time  to  time, 
in  order  that  the  inner  and  outer  pressure  may  thus  be  promptly 

ualized. 

v,          .  The  Internal  Ear,  or  Labyrinth. — The  most  essential  part 
\  ^  ^  of  tihe  organ  of  hearing  is  the  distribution  of  the  auditory  nerve. 
Thip  is  found  within  the  cavity  of  the  internal  ear,  which,  from  its 
*y 'exceedingly  winding  shape,  has  been  termed  the  labyrinth  (see  Fig. 
;-  (T4,  c).      This  cavity  is  hollowed  out  in  dense  bone,  and  consists  of 
\  three  parts — the  vestibule  (a),  or  ante-chamber,  which  is  connected 
with  the  other  two ;    the  cochlea  (b),  or  snail's  shell ;    and  the  three 
semicircular  canals  (c).    The  manner  in  which  the  nerve  of  hearing 
is  distributed  is  remarkable,  and  is  peculiar  to  this  nerve.      In  the 
vestibule  and  the  canals  its  fibres  are  spread  out  over  the  inner 
surface,   not   of    the   bony   cavity,   but  'of    a   membranous   bag, 
which   conforms    to  and    partially   fills    that    cavity,    and    which 
floats  in  it,  being  both  filled  and  surrounded  with  a  clear,  limpid 
fluid. 

101.  A  singular  addition  to  the  mechanism  of  hearing  is  observed 
within  this  membranous  bag  of  the  labyrinth.  This  consists  of  two 
small  oval  ear-stones,  and  a  quantity  of  fine  powder  of  a  calcareous 
nature,  which  is  called  "  ear-sand."  When  examined  under  the 

100.  The  essential  part  of  the  organ  of  hearing?    Its  location?    Formation? 

101.  Where  is  the  "  ear-sand  "  found  ?    Give  the  theory  as  to  its  use. 

12 


• 


266  THE    SPECIAL   SENSES. 

microscope,  these  sandy  particles  are  seen  to  lie  scattered  upon  and 
among  the  delicate  filaments  of  the  auditory  nerve ;  and  it  is  prob- 
able that,  as  the  tremulous  sound-wave  traverses  the  fluid  of  the 
vestibule,  the  sand  rises  and  falls  upon  the  nerve-filaments,  and  thus 
intensifies  the  sonorous  impression. 

102.  In  the  cochlea,  or  snail's  shell,  which  contains  the  fluid,  but 
no  membrane,  the  nerve  branches  upon  a  spiral  shelf,  which,  like 
the  cochlea  itself,  takes  two  and  a  half  turns,  growing  continuously 
smaller  as  it  winds  upward.     As  many  as  three  thousand  nerve- 
fibres  of  different  lengths  have  been  counted  therein ;   these,  it  has 
been  thought,  form  the  grand,  yet  minutely  small  key-board,  upon 
which  strike  all  the  musical  tones  that  are  destined  to  be  conveyed 
to  the  brain.      The  vestibule,  it  is  also  supposed,  takes  notice  of 
noise  as  distinguished  from  musical  sounds  ;  while  the  office  of  the 
semicircular  canals  is,  in  part  at  least,  to  prevent  internal  echoes,  or 
reverberations. 

103.  The  vestibule  communicates  with  the  chain  of  bones  of  the 
middle  ear  by  means  of  a  small  opening,  called  the  "  oval  window," 
or  fenestra  ovalis.     Across  this  window  is  stretched  the  membrane, 
which  has  already  been  alluded  to  as  being  joined  to  the  stirrup- 
bone  of  the  middle  ear.      Through  this  window,  then,  the  sound- 
wave, which  traverses  the  external  and  middle  ear,  arrives  at  last  at 
the  labyrinth.    The  limpid  fluid  which  the  latter  contains,  and  which 
bathes  the  terminal  fibres  of  the  nerve  of  hearing,  is  thus  agitated, 
the  nerve-fibres  are  excited,  and  a  sonorous  impression  is  conducted 
to  the  brain,  or,  as  we  say,  a  sound  is  heard. 

104.  Protection  of  the  Sense  of  Hearing. — From  what  has 
been  seen  of  the  complicated  parts  which  compose  the  organ  of 
hearing,  it  is  evident  that  while  many  of  them  possess  an  exquisite 
delicacy  of  structure,  Nature  has  well  and  amply  provided  for  their 
protection.     We  have  observed  the  concealed  situation  of  the  most 
important  parts  of  the  mechanism  of  the  ear — the  length  of  its  cavity, 
its  partitions,  the  hardness  of  its  walls,  and  its  communication  with 

102.  In  the  cochlea,  or  snail's  shell  ?    "  Key-board  "  in  the  internal  ear  ?    The  vestibules  ? 
Semicircular  canals? 

103.  With  what  does  the  vestibule  communicate?    What  is  the  theory  by  which  sound  is 
conducted  to  the  brain  ? 

104.  The  formation  of  the  organ  of  hearing  with  a  view  to  its  protection? 


THE   SPECIAL  SENSES.  267 

the  atmosphere ;  ail  these  provisions  rendering  unnecessary  any 
supervision  or  care  on  our  part  in  reference  to  the  interior  of  the  ear, 
But  in  respect  to  its  external  parts,  wjiich  are  under  our  control  and 
within  the  reach  of  harm,  it  is  otherwise.  We  may  both  observe 
the  dangers  which  threaten  them,  and  learn  the  means  necessary  to 
protect  them. 

!05.  Caution. — One  source  of  danger  to  the  hearing  consists  in 
lowering  the  temperature  of  the  ear,  especially  by  the  introduction 
of  cold  water  into  the  auditory  canal.  Every  one  is  familiar 
with  the  unpleasant  sensation  of  distension,  and  the  confusion  ol 
sounds  which  accompany  the  filling  of  the  ear  with  water  when 
bathing :  the  weight  of  the  water  within  it  really  distends  tKe 
membrane,  and  the  cold  chills  the  adjacent  sensitive  parts.  It 
is  not  surprising,  therefore,  that  the  frequent  introduction  of  cold 
water,  and  its  continued  presence  in  the  ear,  enfeebles  the  sense 
of  hearing.  Care  should  be  taken  to  remove  water  from  the  ear 
after  bathing,  by  holding  the  head  on  one  side,  and,  at  the  same 
time,  slightly  expanding  the  outer  orifice,  so  that  the  fluid  may 
run  out.  For  a  like  reason,  the  hair  about  the  ears  should  not 
be  allowed  to  remain  wet,  but  should  be  thoroughly  dried  as  soon 
as  possible. 

106.  It  may  be  stated  as  a  general  rule,  to  which  there  are  but 
few  exceptions,  that  no  cold  liquid  should  ever  be  allowed  to  enter 
the  ear.  When  a  wash  or  injection  is  rendered  necessary,  it  should 
always  be  warmed  before  use.  The  introduction  of  cold  air  is  like- 
wise hurtful,  especially  when  it  pours  through  a  crevice  directly  into 
the  ear,  as  it  may  often  do  through  the  broken  or  partially  closed 
window  of  a  car.  The  avoidance  of  this  evil  gives  rise  to  another 
almost  as  great,  namely,  the  introduction  of  cotton  or  other  soft 
substances  into  the  ear  to  prevent  it  from  "  catching  cold."  This 
kind  of  protection  tends  to  make  the  part  unnaturally  susceptible 
to  changes  of  temperature,  and  its  security  seems  to  demand  the 
continued  presence  of  the  "  warm  "  covering.  As  a  consequence  of 
its  presence,  sounds  are  not  naturally  conveyed,  and  the  sensitive- 
ness of  the  nerve  of  hearing  is  gradually  impaired. 

105.  Danger  to  which  the  hearing  may  be  subjected?    Advice  t 

106.  The  general  rule  as  to  the  use  of  water  for  the  ear? 


268  THE    SPECIAL    SENSES. 

107.  The  chief  source  of  injury,  however,  to  the  ear  is  from  the 
introduction  of  solid  substances  into  the  auditory  canal,  with  the 
design  of  removing  insects  or  other  foreign  objects  that  have  found 
their  way  into  the  ear,  or  with  the  design  of  scraping  out  the  ear- 
wax.     For  displacing  a  foreign  object,  it  is  usually  sufficient  to 
syringe  the  ear  gently  with  warm  water,  the  head  being  so  hold 
that  the  fluid  easily  escapes.     If  a  live  insect  has  gained  entrance 
to  the  ear,  it  may  first  be  suffocated  by  pouring  a  little  oil  upon 
it,   and   afterward  removed   by  syringing   the   ear   as  just   men- 
tioned. 

108.  The  removal  of  ear-wax  is  generally  unnecessary ;  for,  as 
we  have  before  seen,  Nature  provides  that  the  excess  of  it  shall  be- 
come dry,  and  then  spontaneously  fall  out  in  the  form  of  fine  scales. 
The  danger  from  the  introduction  of  solid  implements  into  the  outer 
ear  is  chiefly  found  in  the  fact  that  the  membrane  which  lies  at  the 
bottom  of  it  is  very  fragile,  and  that  any  injury  of  it  is  liable  to 
impair  permanently  the  hearing  of  the  injured  ear. 

109.  How  Alcohol  affects  the  Special  Senses. — The  narcotic 
or  benumbing  influence  of  alcohol  is  felt  by  all  forms  of  nervous 
tissue,  and  among  them  the  nerves  of  special  sense.     Vision  is  more 
susceptible  of  injury  by  this  poison  than  any  of  the  other  senses, 
and  it  may  be  either  slightly  impaired  or  wholly  lost.     There  is,  in 
such  cases,  a  progressive  loss  of  power  in  the  optic  nerve  that  can 
only  be  remedied  by  a  perpetual  abandonment,  on  the  part  of  the 
sufferer,  of  alcoholic  drink ;  and  even  this  must  not  be  delayed  too 
long  after  dimness  of  sight  has  commenced. 

110.  Alcohol  and  Color-Blindness. — Progressive  loss  of  color- 
perception  has  been  noticed  by  physicians  in  persons  who  use  liquor 
habitually,  though  not  to  the  extent  of  intoxication.     This  form  of 
gradually  growing  "  color-blindness "  becomes  a  matter  of  highest 
importance,  since  it  may  occur  in  a  railroad  engineer,  or  pilot,  who 
drinks,  or  in  the  case  of  some  official  responsible  for  the  lives  and 
limbs  of  travel  by  steam.     No  persons  who  indulge  in  alcoholic 
beverages  can  safely  be  allowed  to  occupy  trusts  of  this  nature. 

107.  Chief  source  of  injury  to  the  ear?    Directions  for  removing  foreign  objects  from  the 
ear  ?    Of  a  live  insect  f 

109.  Do  those  who  drink  alcohol  have  good  vision  ? 

110.  What  about  their  perception  of  color? 


THE   SPECIAL   SENSES.  269 

111.  Effect  of  Alcohol  on   Other  Senses. — Hearing  and  taste 
are  dulled  by  alcohol.     Touch  is  indirectly  robbed  of  its  efficiency 
in  a  certain  proportion  of  cases,  where  a  tremor  of  the  muscles  of 
the  arm,  or  the  "  palsy  of  drunkards,"  occurs.     Fine  penmanship 
or  drawing,  and  the  use  of  keen-edged  tools,  depend  upon  a  delicate 
employment  of  touch ;  but  with  a  hand  that  shakes  like  the  palsied 
limb  of  an  aged  man,  this  becomes  an  impossibility.     In  this  way 
has  alcohol  deprived  many  a  man  of  the  means  of  his  livelihood. 
This  is  said  to  be  especially  true  of  those  who  belong  to  the  class 
of  topers  who  drink  little  and  often.     (Read  Note  13,  Page  210.) 

112.  False  Apparitions  due  to  Alcohol — Delirium  Tremens. — 
In  certain  diseases  the  eyes  appear  to  see  objects  that  do  not  in 
reality  exist  within  their  view.     High  fever  is  one  of  these  diseases ; 
delirium  tremens,  or  "  the  horrors,"  experienced  by  some  hard  drink- 
ers, is  another.     The  latter  condition  is  marked  by  a  variety  of  ter- 
rifying and  loathsome  creatures ;  if  there  be  any  form  of  reptile 
that  is  especially  repulsive  to  the  delirious  person,  this  is  the  form 
that  is  most  liable  to  haunt  him.     These  false  images  may  be  dimly 
seen  at  first,  but  as  the  disease  progresses  they  generally  become 
perfectly  distinct,  and  real,  and  torturing ;  many  a  victim  has  thrown 
himself  down  from  a  window,  regardless  of  its  height,  in  his  eager 
haste  to  escape  from  his  unreal  visions.     Alarming  sounds,  also,  are 
heard  in  some  cases  of  this  disorder. 

113.  The  Effect  of  Tobacco  upon  Vision. — Oculists  are  nearly 
unanimous  in  the  opinion  that  impairment  of  sight  and  even  its 
utter  loss  may  result  from  tobacco-smoking,  the  optic  nerve  being 
gradually  impaired,  as  in  the  case  of  those  who  lose  their  sight  by 
alcohol,  as  described  in  the  foregoing  paragraph  of  this  Chapter. 
Section  109.    There  is  a  relief  for  this  approaching  blindness  if  the 
patient  will  consent   to  wholly  abstain   from   tobacco;  and  yet, 
"  there  are  those  who  would  rather  smoke  than  see,"  and  persist  in 
the  injurious  habit  in  spite  of  every  proper  medical  caution. 

114.  Certain  narcotic  substances  have  an  injurious  influence  over 
the  sense  of  hearing ;  among  these  are  tobacco  and  coffee  used  in 
excess.     The  opium  habit  is  injurious  to  the  sense  of  sight. 

111.  Other  senses? 

112.  Are  unreal  objects  ever  seen  as  real?    How  is  delirium  tremens  described? 

113.  Has  tobacco  any  influence  over  vision  ? 

114.  Have  alcohol  and  tobacco  together  any  influence ?    Other  injuries? 


270  THE    SPECIAL    SENSES. 


QUESTIONS    FOR    TOPICAL   REVIEW. 

PAOB 

L  What  is  said  of  the  production  of  sensation? , 220 

2.  What  is  said  of  the  variety  of  sensations  ? 221 

8.  What  is  said  of  the  general  sensibility? 221 

4.  What  is  said  of  the  sensation  of  pain 222 

5.  What  is  said  of  the  uses  of  pain  ? 223 

6.  Say  what  you  can  of  the  special  sensation 225 

7.  Say  what  you  can  of  the  organs  of  touch ...» 227 

8.  Say  what  you  can  of  the  sense  of  touch.. 228 

9.  Say  what  you  can  of  the  delicacy  of  touch 22'J 

10.  What  is  understood  by  the  sensations  of  temperature  and  weight  ? 230 

11.  What  is  understood  by  the  organ  of  taste  ? 232 

12.  What  is  understood  by  the  sense  of  taste? 233 

13.  What  is  understood  by  the  relations  of  taste? 234 

14.  Explain  the  influence  of  education,  etc 235 

15.  Explain  the  sense  of  smell 235 

16.  Explain  the  nerve  of  smell 236 

17.  Explain  the  uses  of  the  sense  of  smell 237 

18.  Explain  the  sense  of  sight 240 

19.  Give  the  statement  concerning  light  and  the  optic  nerve 240,  241 

20.  Give  the  statement  concerning  the  organ  of  sight 242 

21.  Give  the  statement  concerning  the  orbits  242,  243 

22.  Give  the  statement  concerning  the  eyelids 243 

23.  Give  the  statement  concerning  the  lachrymal  fluid 244,  245 

24.  Give  the  statement  concerning  the  eyeball 246 

25.  Give  the  statement  concerning  the  iris 248 

26.  Give  the  statement  concerning  the  retina 249,250,  251 

27.  Give  the  statement  concerning  the  crystalline  lens 252 

28.  What  are  the  uses  of  the  lens  ? 253,254 

29.  What  about  long  and  short  sight?.  254,  255 

30.  Explain  the  function  of  accommodation 256,  257 

81.  Explain  old  sight,  or  presbyopia 257 

82.  Explain  hearing  and  sound 258,259,260 

83    Explain  the  external  ear 260,261 

84.  Explain  the  middle  ear? 262,263,264 

85.  Explain  the  internal  ear 265,  266 

36,  What  is  said  of  the  protection  of  the  sense  ofhearing? 266 

87.  What  caution  is  given? 267,  268 


3CU 

THE  VOICE. 

Voice  and  Speech — The  Larynx,  or  the  Organ  of  the  Voice — The  Vocal  Cords— 
The  Laryngoscope — The  Production  of  the  Voice — The  Use  of  the  Tongu& — • 
The  Different  Varieties  of  Voice— The  Change  of  Voice— Its  Compass— 
Purity  of  Tone — Ventriloquy. 

1.  Voice  and  Speech. — In  common  with  the  majority  of  the 
nobler  animals,  man  possesses  the  power  of  uttering  sounds,  which 
are  employed  as  a  means  of  communication  and  expression.    In  man, 
these  sounds  constitute  the  voice ;  in  the  animals  they  are  desig- 
nated as  the  cry.     The  song  of  the  bird  is  a  modification  of  its  cry, 
which  is  rendered  possible  from  the  fact  that  its  respiratory  function 
is  remarkably  active.     The  sounds  of  the  animals  are  generally  pro- 
duced by  means  of  their  breathing  organs.     Among  the  insects, 
they  are  sometimes  produced  by  the  extremely  rapid  vibrations  of 
the  wings  in  the  act  of  flight,  as  in  the  case  of  the  mosquito ;  or  by 
the  rubbing  together  of  hard  portions  of  the  external  covering  of 
the  body,  as  in  the  cricket.     Almost  all  kinds  of  marine  animals 
are  voiceless.     The  tambour-fish  and  a  few  others  have,  however, 
the  power  of  making  a  sort  of  noise  in  the  water.     (Read  Note  i. ) 

2.  But  man  alone  possesses  the  faculty  of  speech,  or  the  power 
to  use  articulate  sounds  in  the  expression  of  ideas,  and  in  the  com- 

1.  Voice  in  Man  and  Animals. — "  The  human  voice,  taking  male  and 
female  together,  has  a  range  of  nearly  four  octaves.  Man's  power  of  speech, 
or  the  utterance  of  articulate  sounds,  is  due  to  his  intellectual  development 
more  than  to  any  great  structural  difference  between  him  and  the  Apes.  Song 
is  produced  by  the  glottis,  speech  by  the  mouth.  The  parrot  and  mocking- 
bird use  the  tongue  in  imitating  human  sounds." — Orion's  Zoology. 


1.  The  uttering  of  sounds  by  animals  ?    How  produced  ? 

2.  The  evidence  of  man's  superior  endowment?    What  is  stated  of  the  idiot?    Parrot? 
Raven? 


272  THE   VOICE. 

munication  of  mind  with  mind.  Speech  is  thus  an  evidence  of  the 
superior  endowment  of  man,  and  involves  the  culture  of  the  intellect. 
An  idiot,  while  he  may  have  complete  vocal  organs  and  full  power 
of  uttering  sounds  or  cries,  is  entirely  incapable  of  speech ;  and,  as 
a  rule,  the  excellence  of  the  language  of  any  people  will  be  found 
to  be  proportional  to  their  development  of  brain.  Man,  however, 
is  not  the  only  being  that  has  the  power  to  form  articulate  sounds, 
for  the  parrot  and  the  raven  may  also  be  taught  to  speak  by  rote; 
but  man  alone  attaches  meaning  to  the  words  and  phrases  he  em- 
ploys. 

3.  Relation  to  Hearing „ — Speech  is  intimately  related  to  the 
sense  of  hearing.  A  child  born  deaf  is,  of  necessity,  dumb  also ; 
not  because  the  organs  of  speech  are  imperfect,  for  he  can  utter 
cries  and  may  be  taught  to  speak,  and  even  to  converse  in  a  rude 
and  harsh  kind  of  language;  but  because  he  can  form  no  accurate 
notion  of  sound.  A  person,  whose  hearing  is  not  delicate,  or  as 
it  is  commonly  expressed,  who  "  has  no  ear  for  music,"  cannot  sing 
correctly.  A  person  who  has  impaired  hearing  commonly  talks  in 
an  unnaturally  loud  and  monotonous  voice.  These  examples  show 
the  necessary  relation  of  intelligence  and  the  sense  of  hearing  with 
that  form  of  articulate  voice,  which  is  termed  speech.  (Read  Note  2.) 

2.  Certain  Peculiarities  of  the  Voice. — "Voice  is  a  sound  produced 
in  the  throat  by  the  passage  of  the  air  through  the  glottis,  as  it  is  expelled 
from  the  lungs.  It  is  grave  and  strong  in  man,  soft  and  higher  in  women  ; 
it  varies  according  to  age.  It  is  alike  in  both  sexes  in  infancy,  but  is  modified 
in  youth  ;  then  the  voice  is  said  to  '  change.'  In  the  young  woman  it  descends 
a  note  or  two,  and  becomes  stronger.  In  the  young  man  the  change  is  much 
more  strongly  marked.  At  the  fourteenth  or  fifteenth  year  the  voice  loses  its 
regularity,  becomes  harsh  and  unequal ;  the  high  notes  cannot  be  sounded, 
while  the  grave  ones  make  their  appearance.  A  year  is  generally  sufficient  for 
this  change  to  be  complete,  and  the  voice  of  the  child  gives  place  to  that  of 
the  man.  Exercise  of  the  voice  in  singing  should  be  very  moderate,  if  not 
entirely  suspended,  while  this  change  is  going  on.  Yoice  k  divided  into  sing- 
ing and  speaking  voice.  One  differs  from  the  other  almost  as  much  as  noises 
do  from  musical  sounds.  It  is  the  short  duration  of  speaking  sounds  which 
distinguishes  them  from  those  of  singing.  This  is  proved  by  the  fact  that  if 
we  prolong  the  intonation  of  a  syllable,  or  utter  it  like  a  note,  the  musical 


3.  Speech  and  hearing?    A  deaf  child?    Person  having  "no  ear  for  music?"    Impaired 
hearing?    What  do  the  examples  show? 


THE   VOICE.  273 

4.  The  Organ  of  the  Voice. — The  essential  organ  of  the  voice 
is  the  Larynx.     This  has  been  previously  alluded  to  in  its  relation 
to  the  function  of  respiration ;  and,  in  the  chapter  on  that  subject, 
are  figured  the  front  view  of  that  organ  (Fig.  42),  and  its  connec- 
tion with  the  trachea,  tongue,  and  other  neighboring  parts  (Fig.  45). 
It  is  situated  at  the  upper  part  of  the  neck,  at  the  top  of  the 
trachea,  or  tube  by  which  air  passes  into  and  out  of  the  lungs.    The 
framework  of  the  larynx  is  composed  of  four  cartilages,  which  ren- 
der it  at  once  very  strong  and  sufficiently  flexible  to  enable  it  to 
move  according  to  the  requirements  of  the  voice. 

5.  The  names  of  the  cartilages  are  (1)  the  thyroid,  which  is  a 
broad,  thin  plate,  bent  in  the  middle  and  placed  in  the  central  line 
of  the  front  part  of  the  neck,  where  it  is  known  as  the  pomum 
Adami,  or  Adam's  apple  (Fig.   66,  B),  and  where  it  may  be  felt 
moving  up  and  down  with  each  act  of  swallowing ;  (2)  the  cricoid, 
which  is  shaped  like  a  seal  ring,  with  the  'broad  part  placed  poste- 
riorly (Fig.  66,  E).     At  the  top  of  the  cricoid  cartilage  are  situated 
the  two  small  arytenoid  cartilages,  the  right  one  of  which  is  shown 
in  Fig.  66,  c.     These  latter  little  organs  are  much  more  movable 

sound  becomes  evident.  And  if  we  pronounce  all  the  syllables  of  a  phrase  in 
the  same  tone,  the  speaking  voice  closely  resembles  psalm-singing.  Every  one 
must  have  noticed  this  in  hearing  school-boys  recite  or  read  in  a  monotone, 
and  the  analogy  is  complete  when  the  last  two  or  three  syllables  are  pro- 
nounced in  a  different  tone.  Spoken  voice  is  moreover  always  a  chant  more 
or  less  marked,  according  to  the  individual  and  the  sentiment  expressed.  The 
accentuation  peculiar  to  certain  languages  also  gives  the  speech  the  character 
of  a  chant ;  to  a  French  ear  an  Italian  preacher  seems  always  to  sing.  A  chant 
also  is  caused  by  those  inflections  of  the  voice,  which  express  our  emotions  and 
our  passions.  They  extend  from  the  feeble  murmur,  which  the  ear  scarcely 
perceives,  to  the  piercing  cry  of  pain.  Affectionate,  sympathetic,  imperious, 
or  hostile,  they  sometimes  charm,  sometimes  irritate,  and  always  move  us.  It 
It  is  related  of  Gretry,  that  he  amused  himself  by  noting  as  exactly  as  pos- 
sible the  '  Bonjour,  monsieur ! '  of  the  persons  who  visited  him ;  and  these 
words  expressed  by  their  intonation,  in  fact,  the  most  opposite  sentiments, 
although  literally  the  same.  Baron,  the  comedian,  moved  his  audience  to 
tears  by  his  recitation  of  the  stanzas  of  the  song,  '  Si  le  roi  m'avait  donne 
Paris  sa  grand1  mile.' — If  the  king  had  given  me  Paris  his  great  city. " — IA 
Pileur  on  Wonders  of  the  Human  Body. 

4.  Organ  of  the  voice  ?    Where  situated  ?    Of  what  is  its  framework  composed  ? 

5.  Names,  formation,  and  situation  of  the  cartilages  ? 


274 


THE   VOICE. 


than  the  other  two,  and  are  very  important  in  the  production  of  the 
voice.  They  have  a  true  ball-and-socket  joint,  and  several  small 
muscles  which  contract  and  relax  with  as 
perfect  regularity  and  accuracy  as  any  of  the 
larger  muscles  of  the  body. 

6.  The   interior   of   the  larynx   is    lined 
with   a   very   sensitive    mucous   membrane, 
which   is    much   more   closely   adherent   to 
the  parts  beneath  than  is  usually  the  case 
with  membranes  of   this   description.     The 
epiglottis   (A),    consisting   of  a   single   leaf- 
shaped  piece  of  cartilage,  is  attached  to  the 
front  part  of  the  larynx.     It  is  elastic,  easily 
moved,  and  fits  accurately  over  the  entrance 
to  the  air-passages  below  it.     Its  office  is  to 
guard  these  delicate  passages  and  the  lungs 
against  the  intrusion  of  food  and  other  for- 
eign articles,   when  the   act  of   swallowing 
takes  place.     It   also   assists  in   modifying 
the  voice. 

7.  The  Vocal  Cords. — Within  the  larynx, 
aii<l  stretched  across  it  from  the  thyroid  car- 
tilage  in   front    to   the  arytenoid  cartilages 
behind,  are   placed  the  two    sets    of   folds 
called  the  vocal  cords.     The  upper  of  these, 
one  on  each  side,  are  the  false  cords,  which  are 

comparatively  fixed  and  inflexible.  These  are  not  at  all  essential  to 
the  formation  of  vocal  sounds,  for  they  have  been  injured,  in  those 
lower  animals  whose  larynx  resembles  that  of  man,  without  mate- 
rially affecting  their  characteristic  cries.  Below  these,  one  on  each 
side,  are  the  two  vocal  cords  (Fig.  66,  F),  which  pursue  a  similar 
direction  to  the  false  cords— namely,  from  before  backward.  They 
are  composed  of  a  highly  elastic,  though  strong  tissue,  and  are 
covered  with  a  thin,  tightly-fitting  layer  of  mucous  membrane. 
Their  edges  are  smooth  and  sharply-defined,  and  when  they  meet, 


A,  The  Epiglottis. 

B,  The  Thyroid  Cartilage. 

C,  Arytenoid  Cartilage. 

D,  Ventricle  of  the  Larynx 

E,  Cricoid  Cartilage. 

F,  Right  Vocal  Cord. 
H,  The  Trachea. 


6.  Lining  of  the  interior  of  the  larynx  ?    The  epiglottis  ? 

7.  Where  are  the  vocal  cords?    The  false  cords  ?    The  true  cords? 


THE  VOICE.  275 

as  they  do  in  the  formation  of  sounds,  they  exactly  match  each 
other. 

8.  Between  the  true  and  false  vocal  cords  is  a  depression  on 
each  side,  which  is  termed  the  ventricle  of  the  larynx  (Fig.  66,  B). 
The  integrity  of  these  true  cords,  and  their  free  vibration,  are  essen- 
tial to  the  formation  of  the  tones  and  the  modulation  of  the  natural 
voice      This  is  shown  by  the  fact  that,  if  one  or  both  of  these  cords 
are  injured  or  become  diseased,  voice  and  speech  are  weakened ;  or 
when  the  mucous  membrane  covering  them  becomes  thickened,  in 
consequence  of  a  cold,  the  vocal  sounds  are  rendered  husky  and 
indistinct.     When  an  opening  is  made  in  the  throat  below  the 
cords — as  not  infrequently  occurs  in  consequence  of  an  attempt  to 
commit  suicide — voice  is  impossible  except  when  the  opening  is 
closed  by  external  pressure. 

9.  The  interval  or  space  between  the  true  cords  of  the  voice  13 
constantly  varying,  not  only  when  their  vocal  function  is  in  exer- 
cise, but  also  during  the  act  of 

respiration.  Every  time  the 
lungs  are  inflated,  the  space 
increases  to  make  wide  the 
entrance  for  the  air,  and  di- 
minishes slightly  during  expi- 
ration. So  that  these  little 
cords  move  gently  to  and  fro 
in  rhythm  with  the  expansion 
and  contraction  of  the  chest 
in  breathing.  These  move- 
ments and  others  may  be  seen  Fl°-  67-vA  VlEW  OF  THE  VocAL  CoRDS  BY 
J  MEANS  OF  THE  LARYNGOSCOPE. 

to  take  place,  if  a  small  mir- 
ror attached  to  a  long  handle  be  placed  back  into  the  upper  part  of  the 
throat ;  the  handle  near  the  mirror  must  be  bent  at  an  angle  of  45°, 
so  that  we  may  look  "  around  the  corner,"  so  to  speak,  behind  the 
tongue.  The  position  which  the  mirror  must  assume  will  be  under- 
stood by  reference  in  Fig.  45.  A  view  of  what  may  be  seen  under 

a.  Where  is  the  ventricle  of  the  larynx  ?  The  essentials  to  the  formation  of  the  tones 
and  modulation  of  the  voice  ? 

9.  Variation  in  the  interval  between  the  true  cords  of  the  voice?  Experiment  with  the 
mirror? 


276  THE   VOICE. 

favorable  circumstances,  during  tranquil  inspiration,  is  represented 
in  Fig.  67.  The  vocal  cords  are  there  shown  as  narrow,  white 
bands,  on  each  side  of  the  central  opening,  and  since  the  image  is 
inverted,  the  epiglottis  appears  uppermost.  The  rings  partly  seen 
through  the  opening  belong  to  the  trachea.  This  little  mirror  is 
the  essential  part  of  an  instrument,  wkich  is  called  the  laryngoscope, 
and  simple  as  it  may  seem,  it  is  accounted  one  of  the  most  valuable 
of  the  recently-invented  appliances  of  the  medical  art. 

10.  The  Production  of  the  Voice. — During  ordinary  tranquil 
breathing,  no  sound  is  produced  in  the  larynx,  true  vocal  tones 
being  formed  only  during  forcible  expiration,  when,  by  an  effort  of 


FIG.  68.— THE  DIFFERENT  POSITIONS  OF  THE  VOCAL  CORDS. 

A,  The  position  during  inspiration.    B,  In  the  formation  of  low  notes.    C,  In  the  formation 

of  high  notes. 

the  will,  the  cords  are  brought  close  together,  and  are  stretched  so 
as  to  be  very  tense.  The  space  between  them  is  then  reduced  to  a 
narrow  slit,  at  times  not  more  than  T^-g-  of  an  inch  in  width  ;  and 
the  column  of  expired  air  being  forced  through  it,  causes  the  cords 
to  vibrate  rapidly,  like  the  strings  of  a  musical  instrument.  Thus 
the  voice  is  produced  in  its  many  varieties  of  tone  and  pitch ;  its 
intensity,  or  loudness,  depending  chiefly  upon  the  power  exerted  in 
expelling  the  air  from  the  lungs.  "When  the  note  is  high,  the  space 
is  diminished  both  in  length  and  width ;  but  when  it  is  low,  the 
space  is  wider  and  longer  (Fig.  68,  B,  c),  and  the  number  of  vibrar 
tions  is  fewer  within  the  same  period  of  time. 

II.  Thf  personal  quality  of  the  voice,  or  that  which  enables  us 
to  recognize  a  person  by  his  speech,  is  mainly  due  to  the  peculiar 
shape  of  the  throat,  nose,  and  mouth,  and  the  resonance  of  the  air 
contained  within  those  cavities.  The  walls  of  the  chest  and  the 
trachea  take  part  in  the  resonance  of  the  voice,  the  air  within 

10.  The  formation  of  true  vocal  tones  ? 

11.  To  what  is  the  personal  quality  of  the  voice  mainly  due  ?    What  aids  are  there  ? 


THE   VOICE.  277 

them  vibrating  at  the  same  time  with  the  parts  above  them.  This 
may  be  tested  by  touching  the  throat  or  breast-bone,  when  a  strong 
vocal  effort  is  made.  The  teeth  and  the  lips  also  are  important,  as 
is  shown  by  the  unnatural  tones  emitted  by  a  person  who  has  lost 
the  former,  or  by  one  who  is  affected  with  the  deformity  known 
as  "hare-lip."  The  tongue  is  useful,  but  not  indispensable  to 
speech ;  the  case  of  a  woman  is  reported,  from  whom  nearly  the 
whole  tongue  had  been  torn  out,  but  who  could,  nevertheless,  speak 
distinctly  and  even  sing. 

12.  The  Varieties  of  voice  are  said  to  be  four  in  number;  two, 
the  bass  and  tenor,  belonging  to  the  male  sex ;  and  two,  the  con- 
tralto or  alto,  and  soprano,  peculiar  to  the  female.     The  baritone 
voice  is  the  name  given  to  a  variety  intervening  between  the  bass 
and  tenor.      In  man,  the  voice  is  strong  and  heavy ;  in  woman, 
soft  and  high.     In  infancy  and  early  youth,  the  voice  is  the  same 
in  both  sexes,  being  of  the  soprano  variety :  that  of  boys  is  both 
clear  and  loud,  and  being  susceptible  of  considerable  training,  is 
highly  prized  in  the  choral  services  of  the  church  and  cathedral 
At  about  fourteen  years  of  age  the  voice  is  said  to  change — that 
is,  it  becomes  hoarse  and  unsteady  by  reason  of  the  rapid  growth 
of  the  larynx.       In  the  case  of  the  girl,  the  change  is   not  very 
marked,  except  that  the  voice  becomes  stronger  and  has  a  wider 
compass ;  but  in  the  boy,  the  larynx  nearly  doubles  its  size  in  a 
single  year,  the  vocal  cords  grow  thicker,  longer,  and  coarser,  and 
the  voice  becomes  masculine  in  character.     During  the  progress  of 
this  change,  the  use  of  the  voice  in  singing  is  injudicious. 

13.  The  ordinary  range  of  each  of  the  four  varieties  of  the  voice 
is  about  two  octaves ;  but  this  is  exceeded  in  the  case  of  several 
celebrated  vocalists.  .  Madame  Parepa  Rosa  has  a  compass  of  three 
full  octaves.     When  the  vocal  organs  have  been  subjected  to  care- 
ful training,  and  are  brought  under  complete  control  of  the  will, 
the  tension  of  the  cords  becomes  exact,  and  their  vibrations  become 
exceedingly  precise  and  true.     Under  these  circumstances  the  voice 
is  said  to  possess  "  purity  "  of  tone,  and  can  be  heard  at  a  great  dis- 
tance, and  above  a  multitude  of  other  sounds.     The  power  of  a 

12.  Varieties  of  voice  ?    The  t)aritone  ?    The  voice  in  early  youth  ? 

18.  The  range  of  the  voice  ?    Result  of  careful  training  of  the  vocal  organs  ? 


278  THE  VOICE. 

pure  voice  to  make  itself  heard  was  recently  exemplified  in  a  strik- 
ing manner  at  a  musical  festival  held  in  an  audience-room  of 
extraordinary  size,  and  amid  an  orchestra  of  a  thousand  instruments 
and  a  chorus  of  twelve  thousand  voices,  the  artist  named  ahove  also 
sang ;  yet  such  was  the  purity  and  strength  of  her  voice  that  its 
notes  could  be  clearly  heard  rising  above  the  vast  waves  of  sound 
produced  by  the  full  accompaniment  of  chorus  and  orchestra. 
(Read Note  I.} 

14.  In  the  production  of  the  articulate  sounds  of  speech,  the 
larynx  is  not  directly  concerned,  but  those  sounds  really  depend 
upon  alterations  in  the  shape  of  the  air-passages  above  that  organ. 
That  speech  is  not  necessarily  due  to  the  action  of  the  larynx  is 
proved  by  the  following  simple  experiment.  Let  an  elastic  tube 
be  passed  through  the  nostril  to  the  back  of  the  mouth.  Then, 
while  the  breath  is  held,  cause  the  tongue,  teeth,  and  lips  to  go 
through  the  form  of  pronouncing  words,  and  at  the  same  time,  let  a 
second  person  blow  through  the  tube  into  the  mouth.  Speech,  pure 

3.  The  Benefits  of  Vocal  Exercise. — "  Reading  aloud  and  recitation  are 
more  useful  and  invigorating  musical  exercises  than  is  generally  imagined,  atleast 
when  managed  with  due  regard  to  the  natural  powers  of  the  individual,  so  as 
to  avoid  effort  and  fatigue.  Both  require  the  varied  activity  of  most  of  the 
muscles  of  the  trunk  to  a  degree  of  which  few  are  conscious,  till  their  attention 
is  turned  to  it.  In  forming  and  undulating  the  voice,  not  only  the  chest,  but 
also  the  diaphragm  and  abdominal  muscles  are  in  constant  action,  and  com- 
municate to  the  stomach  and  bowels  a  healthy  and  agreeable  stimulus ;  and 
consequently,  where  the  voice  is  raised  and  elocution  rapid,  as  in  many  kinds 
of  public  speaking,  the  muscular  effort  comes  to  be  even  more  fatiguing  than 
the  mental.  When  care  is  taken,  however,  not  to  carry  reading  aloud  so  far 
at  one  time  as  to  excite  the  least  sensation  of  soreness  or  fatigue  in  the  chest, 
and  it  is  duly  repeated,  it  is  extremely  useful  in  developing  and  giving  tone  to 
the  organs  of  respiration,  and  to  the  general  system*.  To  the  invigorating 
effects  of  this  kind  of  exercise,  the  celebrated  Cuvier  was  in  the  habit  of  ascrib- 
ing his  own  exemption  from  consumption,  to  which,  at  the  time  of  his  appoint- 
ment to  a  professorship,  it  was  believed  he  would  otherwise  have  fallen  a  sacri- 
fice. The  exercise  of  lecturing  gradually  strengthened  his  lungs  and  improved 
his  health  so  much  that  he  was  never  afterward  threatened  with  any  serious 
pulmonary  disease.  But,  of  course,  this  happy  result  followed  because  the 
exertion  of  lecturing  was  not  too  great  for  the  then  existing  condition  of  his 
lungs. " — Combe's  Physiology. 

14.  The  production  of  the  articulate  sounds  ?    What  experiment  is  mentioned  ? 


THE   VOICE.  279 

and  simple,  or,  in  other  words,  a  whisper  is  produced.  Still  further 
continue  the  experiment,  while  permitting  vocal  sounds  to  be  made, 
and  there  will  be  produced  a  loud  and  whispering  speech  at  the 
same  moment ;  thus  showing  that  voice  and  speech  are  the  result 
of  two  distinct  acts.  Sighing,  in  like  manner,  is  produced  in  the 
mouth  and  throat ;  if,  however,  a  vocal  sound  be  added,  the  sigh  is 
changed  into  a  groan. 

15.  Ventriloquism  is  a  peculiar  modification  of  natural  speech, 
which  consists  in  so  managing  the  voice  that  words  and  sounds  ap- 
pear to  issue,  not  from  the  person,  but  from  some  distant  place,  as 
from  the  chimney,  the  cellar,  or  the  interior  of  a  chest.  The  origi- 
nal meaning  of  the  word  ventriloquism  (that  is,  speaking  from  the 
belly)  indicates  the  early  belief  that  this  mode  of  speech  was  de- 
pendent upon  the  possession  and  use  of  some  special  organ  besides 
the  larynx  and  mouth ;  but  at  the  present  time  it  is  known  that  it 
is  produced  by  these  organs  alone,  and  that  the  sources  of  deception 
consist,  on  the  part  of  the  performer,  in  the  dexterous  management 
of  the  voice,  together  with  a  talent  for  mimicry ;  and,  on  the  part 
of  the  auditory,  in  the  liability  of  the  sense  of  hearing  to  error  in 
respect  to  the  direction  of  sounds.  The  ventriloquist  not  only  seems 
to  "  throw  his  voice,"  as  it  is  said,  or  simulates  the  sound  as  it  usu- 
ally appears  at  a  distance  with  but  little  motion  of  the  lips  and  face, 
but  he  imitates  the  voices  of  an  infant  and  of  a  feeble  old  man,  of 
a  drunken  man  disputing  with  an  exasperated  wife,  the  broken  lan- 
guage of  a  foreigner,  the  cry  of  an  animal  in  distress,  demonstrating 
that  the  performer  must  be  proficient  in  the  art  of  mimicry.  Ven- 
triloquism was  known  to  the  ancient  Romans  and  Greeks ;  and  it  is 
thought  that  the  mysterious  responses  that  were  said  to  issue  from 
the  sacred  trees  and  shrines  of  the  oracles  at  Dodona  and  Delphi 
were  really  uttered  by  priests  who  had  the  power  of  producing  this 
form  of  speech.  (Read  Notes  4  and  5. ) 

4.  Improvement  of  Conversation  by  Vocal  Training. — "For 
years  I  had  fallen  into  a  low,  drawling,  lazy  tone  of  voice  in  my  ordinary  con- 
versation ;  my  utterance  came  forth  in  a  cloud,  and  had  its  dwelling  there. 
From  divers  experiments  and  observations  I  had  long  ago  assured  myself  that 


15.  What  is  ventriloquism?    Indication  of  tlie  original  meaning  of  the  word?    How  are 
the  ventriloquous  sounds  produced  ? 


280  THE   VOICE. 

this  was  a  capital  defect ;  but  this  assurance  had  brought  with  it  no  reform 
Now,  at  last,  I  attempted  it  in  good  earnest.  I  studied  to  bring  myself  out 
of  my  listlessness,  to  acquire  a  rapid,  distinct,  and  articulate  enunciation.  No 
man  can  miss  this  acquisition  unless  from  some  organic  infirmity,  provided 
only  that  he  pursue  it  steadily  and  earnestly.  I  employed  a  variety  of  exer- 
cises for  the  voice,  as  recitation,  the  frequent  repetition  of  the  same  passage, 
slowly  at  first,  and  then  more  quickly,  up  to  my  highest  pitch  of  rapidity,  the 
pronunciation  of  foreign  languages,  Greek  for  the  sake  of  fullness,  and  French 
for  distinctness  and  despatch.  As  a  result,  I  became  comparatively  a  clear 
and  satisfactory  speaker;  and  as  my  talk  was  more  distinct  my  thoughts  were 
all  the  more  pointed  and  precise.  I  acquired  an  evenness  of  tone,  a  confidence, 
a  complacency ;  my  conversation,  as  the  French  say  of  their  language,  went  of 
itself;  I  had  leisure  to  look  chiefly  to  my  direction,  to  march  on  to  my  object." 
— Self-Formation,  by  Capel  Lofft. 

5.  Ventriloquism  and  Sound-Painting. — "  Ventriloquism  bears  the 
same  relation  to  other  phenomena  of  sound  that  perspective  does  to  optical 
phenomena.  The  art  of  perspective  consists  in  portraying  upon  a  flat  surface 
the  appearance  of  objects  at  a  distance  from  it,  so  that  the  same  effect  shall  be 
produced  upon  the  eye  by  the  picture  as  would  be  produced  by  the  objects 
themselves.  In  order  to  do  this,  the  form,  tints,  and  shades  are  reproduced, 
not  as  they  really  are,  but  as  they  are  modified  by  position  and  distance.  Or 
it  may  be  said  to  consist  in  making  and  arranging  a  group  of  objects  so  that 
when  viewed  at  a  given  distance  they  shall  produce  the  same  optical  effect 
produced  by  another  set  of  objects  arranged  in  different  positions  and  at  dif- 
ferent distances. 

"  Ventriloquism  consists  in  making  and  arranging  sounds  so  that  when 
heard  at  a  given  distance  they  shall  produce  the  same  effect  upon  the  ear  that 
another  set  of  sounds  produce  arranged  in  different  positions  and  at  different 
distances. 

"  Sounds  from  a  distance  are  of  course  weakened,  and  they  also  have  another 
quality  which  may  be  compared  to  the  indistinctness  or  outline  in  objects  seen 
at  a  distance.  In  proportion  as  the  fine  ear  of  the  ventriloquist  can  appreciate 
these  modifications  will  be  his  success  in  imitating  distant  sounds.  For  as  to 
see  correctly  is  the  first  essential  to  success  in  drawing,  so  is  hearing  correctly 
the  first  essential  in  ventriloquism. 

"There  are  many  sounds  which  cannot  be  imitated  by  voice  merely,  such 
as  the  singing  of  birds,  the  strident  noise  of  a  saw,  the  whistling  of  a  plane, 
etc.  Such  and  similar  unmusical  sounds  are  imitated  by  means  of  the  teeth, 
the  lips,  or  the  soft  parts  of  the  mouth.  Thus,  the  noise  of  a  saw  is  like  that 
produced  by  hawking,  only  much  prolonged,  and  modified  by  the  cheeks; 
singing  of  birds  may  be  imitated  by  whistling  through  the  teeth  ;  the  foam- 
ing of  soda-water  by  breathing  with  open  lips  into  a  tumbler,  etc.  To  per- 
sons having  a  fine  ear  this  amusing  art  is  not  difficult,  but  we  object  to  the 
name  applied  to  it  It  ought  to  be  called  sound-painting." 


THE    VOICE.  281 


QUESTIONS    FOR  TOPICAL  REVIEW. 

PAGE 

1.  What  distinction  is  made  between  speech  and  voice 271 

2.  What  is  said  of  each? 271 

3.  What  does  speech  usually  indicate? „ 272 

4.  How  is  speech  lelated  to  hearing? 272 

5.  Name  and  describe  the  organ  of  the  voice 273 

6.  What  other  organs  are  concerned  ?. . . . 973 

7.  What  offices  have  the  cartilages? 273 

8.  Explain  and  locate  the  epiglottis 274 

9.  Say  what  you  can  of  the  vocal  cords ,      274 

10.  State  how  a  cold  affects  the  voice 275 

11.  What  does  the  laryngoscope  reveal  to  us? 275 

12.  Upon  what  does  quality  of  voice  depend  ? 276 

13.  What  change  takes  place  when  the  voice  is  raised?. 276 

14.  How  do  the  chest  and  trachea  take  part  ? 276 

15.  How,  the  teeth,  lips  and  tongue? 277 

16.  What  are  the  varieties  of  voice? 277 

17.  What  changes  take  place  with  age? 277 

18.  Mention  the  ordinary  range  of  voice  and  instance  an  exception 277 

19.  What  further  is  said  of  speech  ? 278 

20.  What  is  ventriloquism? 279 

21.  How  produced? < 279 

<Z2.  What  mysteries  does  it  help  to  explain? « 279 


CH-AJTB3R  XII. 

THE  USB  OP  THE  MICROSCOPE  IN  THE  STUDY  OF  PHYSIOLOGY. 

1.  The  Law  of  the  Tissues.— The  will  of  an  infinite  Creator 
is  obeyed  by  atoms  as  well  as  by  worlds.     He  has  seen  fit  to  com- 
mit all  the  functions  of  life  to  structures  or  tissues  so  small  as  to  be 
invisible  to  the  naked  eye.     A  muscle,  for  example,  as  we  have  al- 
ready learned,  is  composed  of  innumerable  filaments,  visible  only  by 
the  aid  of  the  microscope ;  and  the  power  of  the  muscular  mass  is 
but  the  sum  of  the  contractile  power  of  the  filaments  which  enter 
into  its  composition.     Again,  each  cell  of  the  liver,  invisible  to  un- 
assisted sight,  is  a  secreting  organ,  and  the  liver  performs  as  much 
duty  as  the  sum  of  these  minute  organs  renders  possible. 

2.  The  Necessity  of  the  Microscope. — If,  therefore,  we  would 
know  the  real  structure  of  the  human  body,  we  must  make  use  of 
the  microscope.     Our  eyes  are  constructed  for  the  common  offices  of 
life,  to  provide  for  our  wants  and  guard  us  from  the  ordinary  sources 
of  danger ;  but  by  arming  them  with  lenses,  the  real  structure  of 
plants  and  animals  is  revealed  to  our  intelligence ;  and  enemies, 
otherwise  invisible,  that  lie  in  wait  in  the  air  we  breathe,  and  in 
our  daily  food  and  drink,  to  destroy  life,  are  guarded  against. 

3.  Convex  Lenses,  or  magnifying  glasses,  are  disks  of  glass  or 
other  transparent  "substances,  which  have  the  property  of  picturing 
upon  the  retina  of  the  eye  an  image  of  an  object  larger  than  the 
image   produced   there   without   their  aid.      The  glasses  used  in 
microscopes  are  either  double  convex  lenses  (a)  or  plano-convex 
lenses  (&).     If  either  of  these  lenses  be  placed  over  a  hole  in  the 
shutter  of  a  darkened  room,  or  over  the  key-hole  of  a  door,  and  a 
piece  of  paper  be  held  at  a  proper  distance,  a  picure  of  all  objects  in' 

1.  The  will  of  the  Creator,  by  what  obeyed?    The  power  of  a  muscle?    Amount  of  duty 
performed  by  the  liver  ? 

2.  Necessity  for  using  the  microscope?    The  advantages  gained  by  its  use? 

3.  What  are  con  vex  lenses?   Kind  of  lenses  used  in  microscopes?    Experiment?   Picture 
thrown  upon  the  eye  Tt    Derivation  of  the  word  microscope  ? 


THE   MICROSCOPE.  283 

front  of  the  lens  will  be  thrown  on  the  paper,  as  in  the  camera- 
obscura  or  the  magic-lantern.     Now,  in  the  same  manner,  a  lens 
throws  a  picture  of  objects  to  which  it  is  directed  on  the  retina  of 
a  b 

Pro.  69i 

the  eye,  and  when  that  picture  is  larger  than  the  image  made  in  the 
eye  by  the  object  without  the  aid  of  the  lens,  it  is  magnified,  or  the 
lens  has  served  as  a  microscope,  so  called  from  its  use  in  seeing 
small  objects,  from  mikros,  small,  and  skopeo,  to  see. 

4.  Different  Kinds  of  Microscopes. — Microscopes  are  either 
simple  or  compound.     The  glasses  of  magnifying  spectacles,  like 
those   commonly  used  by  aged  persons,  are  simple  microscopes. 
Magnifying  glasses,  mounted  in  frames,  such  as  are  for  sale  by 
opticians  and  others  for  the  detection  of  counterfeit  money,  are 
simple  microscopes,  and  are  useful  in  studying  the  coarser  structure 
of  plants  and  animals. 

5.  The  most  powerful  simple  microscopes  are  made  by  melting 
in  a  flame  a  thread  of  spun  glass,  so  as  to  form  a  minute  globule  or 
bead,  which,  when  set  in  a  piece  of  metal  and  used  to  examine  ob- 
jects on  a  plate  of  glass  held  up  to  the  light,  gives  a  high  magnify- 
ing power.     In  practice,  however,  it  is  found  better  to  use  several 
magnifying  glasses  of  moderate  power  than  a  simple  lens  alone  of 
high  power.     A  combination  of  two  lenses  is  called  a  doublet — of 
three,  a  triplet.     All  simple  microscopes  throw  an  enlarged  image 
of  the  object  upon  the  retina.     Compound  microscopes  are  so  con- 
structed that  the  enlarged  image  of  an  object  is  again  magnified  by 
a  second  lens,  and  hence  their  magnifying  power  is  vastly  superior 
to  that  of  simple  microscopes. 

6.  The  accompanying  diagrams  will  explain  the  action  of  the 

4.  Kinds  of  microscope  f    What  are  simple  microscopes  ? 

5.  Construction  of  the  most  powerful  simple  microscopes?     In  practice?    A  doublet? 
Triplet?    Why  are  compound  microscopes  superior  to  simple  ones? 

6.  Explain,  by  means  of  the  diagram,  the  action  of  the  compound  microscope. 


284  THE   MICROSCOPE. 

compound  microscope  compared  with  that  of  the  simple  microscope. 
In  Fig.  70,  which  represents  the  working  of  the  simple  microscope, 
the  rays  from  the  object  (a  I),  passing  through  the  lens  (L),  form  an 
image  (ar  b')  in  the  retina  of  the  eye  (E),  and  as  all  images  are  in- 
verted in  the  eye,  the  ohject  is  seen  as  all  other  objects  are,  and 
appears  erect.  In  Fig.  71  is  seen  the  action  of  the  compound 
microscope.  An  inverted  image  (a'  V)  of  the  object  (a  b)  is  mag- 
nified by  the  second  lens  (L'),  and  an  erect  image  is  thrown  upon 


Fio.  70. -SIMPLE  MICROSCOPE. 

.e  retina,  which,  as  all  other  objects  seen  erect  with  the  naked  eye 
are  inverted,  gives  to  the  image  a  contrary  direction,  or  inverts  it  to 
e  mind. 

7.  A    Compound    Microscope   consists  of  two   portions:    the 
optical  portion,  or  the  lenses,  and  the  mechanical  portion,  or  the 
instrument  which  bears  the  lenses.     The  glasses  of  a  compound 
microscope  are  two :  the  object-glass  and  the  lower  lens  of  Fig.  71, 
and  the  ocular  or  eye-piece  and  the  upper  piece  of  Fig.  71.    Both  the 
object-glass  and  the  eye-piece  may,  and  usually  do,  consist  of  more 
than  one  lens,  for,  as  has  been  previously  mentioned,  better  results 
are  obtained  by  a  combination  of  lenses  of  moderate  power  than 
by  single  lenses  of  high  power  and  great  curvature. 

8.  How  to  Choose  and  Use  a  Microscope. — No  attractiveness 
in  the  mechanical  part  of  a  microscope  can  compensate  for  inferior 
lenses ;  and  the  very  first  consideration  in  the  choice  of  an  instru- 
ment should  be  the  excellence  of  the  optical  part  of  the  instrument. 
In  the  use  of  the  instrument,  care  should  be  exercised  to  keep  the 
lenses  clean,  free  from  dust,  not  to  press  the  object-glass  upon  the 
object  under  observation,  and  not  to  wet  it  in  the  water  in  which 

7.  Portions,  in  a  compound  microscope ?    The  glasses? 

8.  How  to  choose  a  microscope ?    How  to  use  it? 


THE    MICROSCOPE. 


285 


most  objects  are  examined.  A  good  microscope  requires  its  own 
table ;  and  when  not  in  use,  should  be  covered  by  a  bell  glass,  OP 
a  clean  linen  cloth. 

9.  The  mechanical  portion  of  the  instrument  _*»^^ 
varies  greatly  in  different  instruments.      That 

one  is  the  best  which  is  the  simplest,  the  most 
solid  and  most  easily  managed.  Most  objects  in 
human  anatomy  are  examined  in  water  or  in 
other  liquids,  or  they  are  themselves  liquids; 
ice  an  oblique  stage  is  often  inconvenient. 

10.  Additional  Apparatus. — As  almost  all 
objects   in   human   anatomy   are   examined  by 
transmitted  light  thrown    up  from   the   mirror 
beneath  the  stage  through  the  object  to  the  eye, 
they  must  be  placed  upon  strips  of  clear  glass 
about  three  inches  long  and  one  inch  wide,  com- 
monly called  "  slides."      These    should  be  pro- 
cured with  the  microscope.     Again,  most  objects 
seen  with   high  powers  require  to  be  covered 
with  a  thin  plate  of  glass,  very  properly  called 
a  "cover,"  that  the  moisture  of  the  specimen 
may  not  tarnish  the  object-glass.     Square  or  cir- 
cular covers  of  very  thin  glass  are  therefore  pro- 
vided; and  a  good  supply  of  these  should  be 
always  on  hand.     These  glasses  should  be  kept 
in  a  covered  dish  filled  with  a  mixture  of  alco- 
hol and  water.     Simple  water  will  not  remove 
the  fatty  matter  which  exists  in  all  animal  tis- 
sues, and,  therefore,  the  glasses  cannot  be  thor- 
oughly cleaned  with  it  alone. 

11.  When    glasses    are    required    for    use, 
they  should    be  removed  from  the  liquid  and 
wiped  clean  and  dry  with  a  soft  linen  handker- 
chief.    Delicate  knives,  scissors,  needles  mounted  in  handles,  for- 
ceps, pipettes  or  little  tubes  for  taking  up  water,  should  be  ob- 

9.  The  characteristics  of  the  best  instrument?     What   special   requisites  should  be 
insisted  upon  ?    Why,  as  to  a  horizontal  stage  ? 

10    Slides?    Covers,  square  and  circular ?    How  kept? 

11.  Cleaning  ttie  glasses  ?    Knives,  scissors,  etc.  ?    Various  liquids  T 


FIG.    71.— COMPOUND 
MICROSCOPE. 


286  THE   MICROSCOPE. 

tained;  these  are  essential  to  all  microscopical  study.  The  table 
should  be  supplied  with  glass-stoppered  bottles  containing  the 
various  liquids  ordinarily  used  in  the  study  of  physiology.  Thus, 
tincture  of  iodine  is  indispensable  in  studying  vegetable  structure, 
acetic  acid  in  the  study  of  animal  tissues ;  and  other  articles  will 
have  to  be  added  from  time  to  time,  as  your  progress  in  study 
demands  them. 

12.  Preliminary  Studies. — In  order  to  prepare  the  way  for  the 
study  of  any  department  of  science  with  the  aid  of  the  microscope 
— for  the  microscope  is  but  an  eye,  and  can  be  turned  in  almost  any 
direction  for  purposes  of  investigation — it  is  necessary  to  become 
acquainted  with  the  many  objects  which  are  liable  to  complicate  the 
examination  of  particular  structures.    Both  air  and  water  are  full  of 
floating  bodies,  and  the  most  common  of  these  should  first  occupy 
the  attention.      In  the  city,  particles  of  starch  are  alway  floating  in 
the  air.     Take  a  very  minute  portion  of  wheat  flour,  place  it  in  the 
middle  of  a  clean  glass  "  slide,"  drop  upon  it  a  drop  of  pure  water, 
cover  it  with  a  plate  of  thin  glass,  and  examine  it  with  a  power  of 
from  one  hundred  to  six  hundred  diameters.    It  will  be  found  to  be 
composed  of  minute  grains  or  granules,  the  largest  of  which  are  made 
up  of  coats  or  layers,  like  an  onion,  arranged  around  a  central  spot 
called  the  hilum. 

13.  Make  another  preparation  in  the  same  manner,  and,  after 
adding  the  water  and  before  covering  with  the  thin  glass  cover,  add 
a  small  drop  of  a  solution  of  iodine.     Now,  upon  examining  the 
specimen,  every  grain  will  be  seen  to  be  of  a  beautiful  deep  blue 
color.     After  thus  studying  wheat  starch,  the  starch  of  Indian  corn, 
of  arrow-root,  and  of  various  grains  should  be  examined  in  like 
manner,  and  their  resemblances  and  differences  noted.    The  granules 
of  potato-starch  are  as  distinctly  marked  as  any. 

14.  Fibres  of  cotton,  lint,  and  wool  are  liable  to  be  found  in  every 
specimen  prepared  for  microscopical  examination.    In  order  to  study 
these,  any  cotton,  woolen,  or  linen    fabric,  or  garment,  may  be 
scraped,  and  the  scrapings  placed  on  a  piece  of  glass  moistened  with 


12.  Bodies,  in  air  and  water?    The  examination  of  starch? 

13.  The  examination  with  solution  of  iodine?    Advice  respecting  other  articles? 

14.  Directions  for  examining  cotton  and  other  fibres  ?    Vegetable  hairs  ? 


THB   MICROSCOPE.  287 

water,  covered  with  the  thin  glass  plate  or  cover  as  before,  and  ex- 
amined with  the  same  magnifying  power,  namely,  from  one  hundred 
to  six  hundred  diameters.  Vegetable  hairs  or  down  are  constantly 
floating  in  air  and  water.  These  are  of  very  various  forms, 
are  simple  or  grouped,  and  form  very  interesting  objects  of  study. 
They  are  readily  procured  from  the  epidermis  or  outer  mem- 
brane of  the  leaves  or  stems  of  plants,  by  cutting  with  a  delicate 
Lnife. 

15.  The  tissues  of  plants,  epidermis,  ducts,  and  woody  fibres  are 
constantly  found  in  microscopic  preparations.    They  may  be  studied 
in  delicate  sections  made  with  a  sharp  knife,  or  by  tearing  vegetable 
tissues  apart  with   needles.     The   down  of  moths,  the  hairs  of 
different  animal's,  the  fibres  of  paper,  the  most  common  animalcules 
in  water,  the  dust  of  shelves,  and  generally  the  structures  found  in 
all  vegetable  and  animal  substances  by  which  we  are  surrounded, 
should  be  studied  as  a  preliminary  to  any  special  line  of  micro* 
scopical  investigation. 

16.  The  Study  of  Human  Tissues. — When  this  has  been  done 
and  familiarity  with  the  use  of  the  instrument  has  been  obtained, 
proceed  to  the  study  of  the  human  body,  for  human  physiology  is 
our  subject.     If  the  end  of  the  finger  be  pricked  with  a  pin,  a  drop 
of  blood  may  be  procured  for  examination.    Place  this  on  one  of  the 
glass  slides,  cover  it  with  a  thin  piece  of  glass,  press  down  the  cover 
so  as  to  make  a  thin  layer,  and  then  examine  with  the  magnifying 
power  just  mentioned.      Do  not  add  water,  for  that  will  cause  the 
blood  corpuscles  to  disappear.     If  the  drop  of  blood  is  placed  under 
the  microscope  at  once  after  being  drawn  from  the  finger,  most  in- 
teresting phenomena  will  be  observed.      The  red  corpuscles  will  be 
seen  to  arrange   themselves  in  rows,   like   piles  of  coin,  while 
the  blood  is  coagulating.      The  spherical,  white  corpuscles  will  be 
left  out  of  the  rows  of  red  disks,  and,  if  the  highest  power  be  used, 
will  be  seen  to  change  their  shape  constantly. 

17.  If  you  scrape  with  a  dull  knife  the  inside  of  the  cheek,  the 
flattened  scales  of  "  pavement  epithelium,"  or  of  the  insensible  cov« 


15.  Directions  for  examining  various  tissues  ?    Down  of  moths  and  other  structures  ? 

18.  Directions  for  examining  a  drop  of  blood  ? 

17.  Examination  of  the  scales  of  the  mouth  ?    Dandruff? 


288  THE   MICROSCOPE. 

ering  which,  analogous  to  the  scarf-skin  on  the  outer  surface  of  the 
body,  lines  the  cavities  of  its  interior,  may  be  readily  studied. 
They  have  the  appearance  of  transparent  tiles,  each  enclosing  a 
round  or  oval  body,  called  its  nucleus.  Dandruff  and  the  scrapings 
from  the  skin  of  the  body  are  composed  of  scales  like  those  of  the 
mouth,  but  they  differ  somewhat  in  being  hardened  by  horny 
matter,  and  in  having  a  very  faint  central  body  or  nucleus. 

18.  The  Tissues  of  the  Inferior  Animals. — The  warm-blooded 
animals  do  not  differ  in  the  tissues  or  microscopic  structures  that  com- 
pose them,  but  only  in  the  amount  and  arrangement  of  these  tissues. 
Milne-Edwards  says  these  tissues  "  do  not  differ  much  in  different 
animals,  but  their  mode  of  association  varies,  and  it  is  chiefly  by 
reason  of  the  differences  in  the  combination  of  these  associations  in 
various  degrees,  that  each  species  possesses  the  anatomical  properties 
and  characters  which  are  peculiar  to  it." 

19.  Hence  the  butcher's  stall  will  furnish  all  the  materials  for  the 
study  of  the  microscopic  tissues.     The  structure  of  the  heart,  lungs, 
liver,  brain,  and  muscle,  may  all  be  studied,  and  well  studied,  by 
using  minute  pieces  of  the  flesh  of  the  lower  animals,  especially  of 
the  quadrupeds.     Such  portions  of  these  animals  as  are  not  exposed 
for  sale  can  be  readily  obtained  by  order  from  the  slaughter-house. 
To  examine  with  the  powers  of  which  we  liave  been  speaking,  it  is 
only  necessary  to  cut  off  exceedingly  small  pieces,  tear  them  apart 
with  needles,  or  make  very  delicate  sections  with  a  sharp  knife. 

20.  Incentives  to  Study. — A  complete  knowledge  of  all  minute 
structures  is  not  to  be  expected  at  once,  for  you  are  here  introduced 
into  a  new  realm  of  Nature,  a  world  of  little  things  as  vast,  as  won- 
derful, and  as  carefully  constructed  as  the  starry  firmanent — that 
other  realm  of  grand  objects  which  the  astronomer  nightly  scans 
with  the  telescope.     It  will  not  appear  singular,  therefore,  if,  at 
first,  you  feel  strange  and  awkward  in  this  new  creation.     With  a 
little  perseverance,  however,  and  with  the  attention  directed  toward 
simple  objects  at  the  outset,  it  will  not  be  long  before  an  increasing 
experience  will  engender  confidence. 

21.  If  to  all  this  there  be  added  an  enthusiastic  study  of  the 

18.  In  what,  as  respects  the  tissues,  do  the  warm-blooded  animals  differ?    Statement  of 
Milne-Edwards? 

18.  How  to  procure  materials  for  the  study  of  the  tissues  of  man? 


THE   MICROSCOPE. 


289 


standard  authorities  on  the  subject,  the  rate  of  progress  will  be 
much  more  rapid.  As  compared  with  similar  studies,  few  possess 
more  interest  than  microscopy,  and  to  the  one  who  pursues  it  with 
fondness,  it  constantly  affords  sources  of  pleasure  and  agreeable  sur- 
prises ;  and  in  the  end  often  leads  to  new  and  valuable  additions 
to  the  sum  of  human  knowledge.  The  depths  which  the  micro- 
ecope  is  employed  to  fathom  are  no  more  completely  known  than 
are  the  heights  above  us  explored  and  comprehended  by  the 
astronomer. 


QUESTIONS    FOR    TOPICAL    REVIEW. 


1  Say  what  you  can  of  the  law  of  the  tissues 2S2 

2.  What,  then,  is  the  necessity  of  the  microscope  ? 282 

3.  Define  and  state  use  of  convex  lenses 283 

4.  Name  some  of  the  kinds  of  microscopes 288 

5.  Explain  action  of  compound  microscope. 283 

ft  Of  what  parts  does  it  consist? 284 

7.  What  parts  are  of  most  importance? 284 

8.  How  would  yon  prepare  specimens?. 285 

9-  What  further  directions  are  given? 285,236 

10.  What  is  said  of  preliminary  studies?. , 286 

11.  Give  statement  regarding  study  of  human  tissues ..., 287 

12.  Tissues  of  inferior  animals 28£ 


APPENDIX. 


Poisons  and  their  Antidotes. 

ACCIDENTS  from  poisoning  are  of  such  frequent  occurrence,  that  every  one 
should  be  able  to  administer  the  more  common  antidotes,  until  the  services  of 
a  physician  can  be  obtained.  As  many  poisons  bear  a  close  resemblance  to 
articles  in  common  use,  no  dangerous  substance  should  be  brought  into  the 
household  without  having  the  word  poison  plainly  written  or  printed  on  the 
label ;  and  any  package,  box,  or  vial,  without  a  label,  should  be  at  once 
destroyed,  if  the  contents  are  not  positively  known. 

"When  a  healthy  person  is  taken  severely  and  suddenly  ill  soon  after  some 
substance  has  been  swallowed,  we  may  suspect  that  he  has  been  poisoned.  In 
all  cases  where  poison  has  been  taken  into  the  stomach,  it  should  be  quickly 
and  thoroughly  expelled  by  some  active  emetic,  which  can  be  speedily  ob- 
tained. This  may  be  accomplished  by  drinking  a  tumblerful  of  warm  water, 
containing  either  a  tablespoonful  of  powdered  mustard  or  of  common  salt,  or 
two  teaspoonfuls  of  powdered  alum  in  two  tablespoonfuls  of  syrup.  "When 
vomiting  has  already  taken  place,  it  should  be  continued  by  copious  draughts 
of  warm  water  or  mucilaginous  drinks,  such  as  gum- water  or  flaxseed  tea,  and 
tickling  the  throat  with  the  finger  until  there  is  reason  to  believe  that  all  of 
the  poisonous  substance  has  been  expelled  from  the  stomach. 

The  following  list  embraces  only  the  more  common  poisons,  together  with 
guch  antidotes  as  are  usually  at  hand,  to  be  used  until  the  physician  arrives. 

Poisons. 

Acids. — Hydrochloric  acid;  muriatic  acid  (spirits  of  salt);  nitric  acid  (aqua 
fortis);  sulphuric  acid  (oil  of  vitriol). 

ANTIDOTE. — An  antidote  should  be  given  at  once  to  neutralize  the  acid. 
Strong  soapsuds  is  an  efficient  remedy,  and  can  always  be  obtained.  It  should 
be  followed  by  copious  draughts  of  warm  water  or  flaxseed  tea.  Chalk,  mag- 
nesia, soda,  or  saleratus  (with  water),  or  lime-water,  are  the  best  remedies. 
When  sulphuric  acid  has  been  taken,  water  should  be  given  sparingly,  because, 
when  water  unites  with  this  acid,  intense  heat  is  produced. 

Oxalic  acid. 

ANTIDOTE. — Oxalic  acid  resembles  Epsom  salts  in  appearance,  and  may 


APPENDIX.  291 

easily  be  mistaken  for  it     The  antidotes  are  magnesia,  or  chalk  mixed  with 
water. 

Prussic  Acid;  oil  of  Utter  almonds;  laurel  water;  cyanide  of  potassium 
(used  in  electrotyping). 

ANTIDOTE. — Cold  douche  to  the  spine.  Chlorine  water,  or  water  of 
ammonia  largely  diluted,  should  be  given,  and  the  vapor  arising  from  them 
may  be  inhaled. 

Alkalies  and  their  Salts. — AMMONIA  (hartshorn),  liquor  or  water  of  am- 
monia. POTASSA  : — caustic  potash,  strong  lye,  carbonate  of  potassa  (pearlash), 
nitrate  of  potassa  (saltpetre). 

ANTIDOTE. — Give  the  vegetable  acids  diluted,  as  weak  vinegar,  acetic,  citric, 
or  tartaric  acids  dissolved  in  water.  Castor  oil,  linseed  oil,  and  sweet  oil  may 
also  be  used  ;  they  form  soaps  when  mixed  with  the  free  alkalies,  which  they 
thus  render  harmless.  The  poisonous  effects  of  saltpetre  must  be  counteracted 
by  taking  mucilaginous  drinks  freely,  so  as  to  produce  vomiting. 

Alcohol. — Brandy,  wine;  all  spirituous  liquors. 

ANTIDOTE.  — Give  as  an  emetic  ground  mustard  or  tartar  emetic.  If  the  pa- 
tient cannot  swallow,  introduce  a  stomach  pump  ;  pour  cold  water  on  the  head. 

Gases. — Chlorine,  carbonic  acid  gas,  carbonic  oxide,  fumes  of  burning  char- 
coal, sulphuretted  hydrogen,  illuminating  or  coal-gas. 

ANTIDOTE. — For  poisoning  by  chlorine,  inhale,  cautiously,  ammonia  (harts- 
horn). For  the  other  gases,  cold  water  should  be  poured  upon  the  head,  and 
stimulants  cautiously  administered;  artificial  respiration.  (See  Marshall 
HalVs  Ready  Method,  page  293. ) 

Metals. — Antimony,  tartar  emetic,  wine  of  antimony,  etc. 

ANTIDOTE. — If  vomiting  has  not  occurred,  it  should  be  produced  by  tickling 
the  throat  with  the  finger  or  a  feather,  and  the  abundant  use  of  warm  water. 
Astringent  infusions,  such  as  common  tea,  oak  bark,  and  solution  of  tannin, 
act  as  antidotes. 

Arsenic. — White  arsenic,  Fowler's  solution,  fly-powder,  cobalt,  Paris  green, 
etc. 

ANTIDOTE. — Produce  vomiting  at  once  with  a  tablespoonful  or  two  of  pow- 
dered mustard  in  a  glass  of  warm  water,  or  with  ipecac.  The  antidote  is  hy- 
drated  peroxide  of  iron.  If  Fowler's  solution  has  been  taken,  lime-water  must 
be  given. 

Copper. — Acetate  of  copper  (verdigris),  sulphate  of  copper  (blue  vitriol),  food 
cooked  in  dirty  copper  vessels,  or  pickles  made  green  by  copper. 

ANTIDOTE. — Milk  or  white  of  eggs,  with  mucilaginous  drinks  (flaxseed  tea, 
etc. ),  should  be  freely  given. 

Iron. — Sulphate  of  iron  (copperas),  etc. 

ANTIDOTE. — Carbonate  of  soda  in  some  mucilaginous  drink,  or  in  water,  is 
an  excellent  antidote. 

Lead.— Acetate  of  lead  (sugar  of  lead),  carbonate  of  lead,  (white  lead),  water 
kept  in  leaden  pipes  or  vessels,  food  cooked  in  vessels  glazed  with  lead. 


292  APPENDIX. 

ANTIDOTE.  — Induce  vomiting  with  ground  mustard  or  common  salt  in  warm 
water.  The  antidote  for  soluble  preparations  of  lead  is  Epsom  salts;  for  the 
insoluble  forms,  sulphuric  acid  largely  diluted. 

Mercury. — Si-chloride  of  mercury  (corrosive  sublimate),  ammoniated  mer- 
cury (white  precipitate),  red  oxide  of  mercury  (red  precipitate),  red  sulphuret 
of  mercury  (vermillion). 

ANTIDOTE. — The  white  of  eggs,  or  wheat  flour  beaten  up  with  water  and 
milk,  are  the  best  antidotes. 

Silver. — Nitrate  of  silver  (lunar  caustic). 

ANTIDOTE. — Givs  a  teaspoonful  of  common  salt  in  a  tumbler  of  water.  It 
decomposes  the  salts  of  silver  and  destroys  their  activity. 

Zinc. — Sulphate  of  zinc,  etc.  (white  vitriol). 

ANTIDOTE. — The  vomiting  may  be  relieved  by  copious  draughts  of  warm 
water.  The  antidote  is  carbonate  of  soda  administered  in  water. 

Narcotic  Poisons. — Opium  (laudanum,  paregoric,  salts  of  morphia,  God- 
frey's cordial,  Dalby's  carminative,  soothing  syrup,  cholera  mixtures),  aconite, 
belladonna,  hemlock,  stramonium,  digitalis,  tobacco,  hyosciamus,  nux  vomica, 
strychnine. 

ANTIDOTE. — Evacuate  the  stomach  by  the  most  active  emetics,  as  mustard, 
alum,  or  sulphate  of  zinc.  The  patient  should  be  kept  in  motion,  o,nd  cold 
water  dashed  on  the  head  and  shoulders.  Strong  coffee  must  be  given.  The 
physician  will  use  the  stomach  pump  and  electricity.  In  poisoning  by  nux 
vomica  or  strychnine,  etc.,  chloroform  or  ether  should  be  inhaled  to  quiet  the 
spasms. 

Irritant  Vegetable  Poisons. — Croton  oil,  oil  of  savine,  poke,  oil  of  tansy, 
etc. 

ANTIDOTE. — If  vomiting  has  taken  place,  it  may  be  rendered  easier  by 
copious  draughts  of  warm  water.  But  if  symptoms  of  insensibility  have  come 
on  without  vomiting,  it  ought  to  be  immediately  excited  by  ground  mustard 
mixed  with  warm  water,  or  some  other  active  emetic,  and  after  its  oper- 
ation an  active  purgative  should  be  given.  After  evacuating  as  much  of  the 
poison  as  possible,  strong  coffee  or  vinegar  and  water  may  be  given  with  ad- 
vantage. 

Poisonous  Fish. — Conger  eel,  mussels,  crabs,  etc. 

ANTIDOTE. — Evacuate,  as  soon  as  possible,  the  contents  of  the  stomach  and 
bowels  by  emetics  (ground  mustard  mixed  with  warm  water  or  powderedalum), 
and  castor  oil,  drinking  freely  at  the  same  time  of  vinegar  and  water.  Ether, 
with  a  few  drops  of  laudanum  mixed  with  sugar  and  water,  may  afterward  be 
taken  freely. 

Poisonous  Serpents.— ANTIDOTE.— A  ligature  or  handkerchief  should  be 
applied  moderately  tight  above  the  bite,  and  a  cupping-glass  over  the  wound. 
The  patient  should  drink  freely  of  alcoholic  stimulants  containing  a  small 
quantity  of  ammonia.  The  physician  may  inject  ammonia  into  the  veins. 

PoiSOTIOUS  Insects.— Stings  of  scorpion,  hornet,  wasp,  bee,  etc. 


APPENDIX.  293 

ANTIDOTE. — A  piece  of  rag  moistened  with  a  solution  of  carbolic  acid  may 
be  kept  on  the  affected  part  until  the  pain  is  relieved ;  and  a  few  drops  of  car- 
bolic acid  may  be  given  frequently  in  a  little  water.  The  sting  may  be 
removed  by  making  strong  pressure  around  it  with  the  barrel  of  a  sznall  watch- 
key. 

Drowning-. 

MARSHALL  HALL'S  "  READY  METHOD  "  of  treatment  in  asphyxia  froa 
drowning,  chloroform,  coal-gas,  etc. 

1st.  Treat  the  patient  instantly  on  the  spot,  in  the  open  air,  freely  exposing 
the  face,  neck,  and  chest  to  the  breeze,  except  in  severe  weathev. 

2d.  In  order  to  clear  the  throat,  place  the  patient  gently  on  the  face,  with 
one  wrist  under  the  forehead,  that  all  fluid,  and  the  tongue  itself,  may  fall  for- 
ward, and  leave  the  entrance  into  the  windpipe  free. 

3d.  To  excite  respiration,  turn  the  patient  slightly  on  his  side,  and  apply 
some  irritating  or  stimulating  agent  to  the  nostrils,  as  veratrine,  dilute  am- 
monia, etc. 

4th.  Make  the  face  warm  by  brisk  friction ;  then  dash  cold  water  upon  it 

5th.  If  not  successful,  lose  no  time ;  but,  to  imitate  respiration,  place  the 
patient  on  his  face,  and  turn  the  body  gently,  but  completely  on  the  side,  and 
a  little  beyond;  then  again  on  the  face,  and  so  on,  alternately.  Repeat  these 
movements  deliberately  and  perse veringly,  fifteen  times  only  in  a  minute. 
(When  the  patient  lies  on  the  thorax,  this  cavity  is  compressed  by  the  weight 
of  the  body,  and  orpiration  takes  place.  When  he  is  turned  on  the  side,  this 
pressure  is  removed,  and  inspiration  occurs. ) 

6th.  When  the  prone  position  is  resumed,  make  a  uniform  and  efficient 
pressure  along  the  spine,  removing  the  pressure  immediately,  before  rotation  on 
the  side.  (The  pressure  augments  the  earpiration,  the  rotation  commences  in- 
spiration. )  Continue  these  measures. 

7th.  Rub  the  limbs  upward,  with  firm  pressure  and  with  energy.  (The  ob- 
ject being  to  aid  the  return  of  venous  blood  to  the  heart. ) 

8th.  Substitute  for  the  patient's  wet  clothing,  if  possible,  such  other  cover- 
ing as  can  be  instantly  procured,  each  bystander  supplying  a  coat  or  cloak, 
etc.  Meantime,  and  from  time  to  time,  to  excite  inspiration,  let  the  surface  ol 
the  body  be  slapped  briskly  with  the  hand. 

9th.  Rub  the  body  briskly  until  it  is  dry  and  warm,  then  dash  cold  water 
upon  it,  and  repeat  the  nibbing. 

Avoid  the  immediate  removal  of  the  patient,  as  it  involves  a  dangerous  loss 
of  time;  also,  the  use  of  bellows,  or  any  forcing  instrument ;  also,  the  warm 
booth,  and  all  rough  treatment. 

The  Care  of  the  Sick-Room. 

The  sick-room  should  be  bright  and  airy,  and  "Sweetness  and  light"  its 
motto.  Other  things  being  equal,  it  is  best  on  one  of  the  upper  floors — in  the 


294  APPENDIX. 

case  of  some  "catching"  disease  on  the  top  floor.  Let  it  be  on  the  sunny  side 
of  the  house.  If  for  any  reason  the  light  of  the  sun  is  temporarily  to  be 
avoided — as  when  the  eyes  are  sensitive  or  have  been  operated  upon — let  the 
light  be  shut  out  by  a  proper  arrangement  of  blinds  or  curtains.  The  air- 
supply  to  be  breathed  by  the  sick  person  should  be  pure.  Those  who,  in  health, 
find  themselves  in  an  impure  air  can  quit  it ;  they  are  not  compelled  to  suffer 
from  it ;  but  a  sick  person  may  be  incapable  of  recognizing  the  bad  quality  of 
the  air,  as  well  as  helpless  to  free  himself  from  it 

To  keep  the  air  pure,  the  windows  should  be  opened  as  often  as  three  times 
a  day,  care  being  taken  to  protect  the  patient  from  being  chilled,  while  the 
room  is  being  aired 

Unless  the  physician  shall  direct  differently,  one  window — that  most  remote 
from  the  bed — should  be  open  an  inch  or  more  both  day  and  night,  and  in  all 
seasons.  The  extent  to  which  the  sash  shall  be  lowered  must  be  governed 
largely  by  the  weather  and  the  direction  of  the  wind. 

A  fire,  in  an  open  fireplace,  except  in  summer  weather,  will  be  a  great  help 
towards  keeping  the  air  pure.  The  upward  current  through  a  chimney-flue,  if 
nnobstructed,  is  equal  to  or  not  far  below  20,000  cubic  feet  per  hour;  an  outlet 
sufficient  for  a  room  occupied  by  ten  persons. 

The  inlet  of  air,  however,  must  not  be  forgotten,  otherwise  the  air  of  the 
room  tends  to  become  both  impure  and  too  thin.  As  our  houses  are  generally 
constructed,  the  inlet  of  air  is  best  secured  by  a  window-sash  being  lowered 
from  the  top. 

Take  special  care  that  no  stationary  wash-basin  or  other  sewer-connected  con- 
venience is  improperly  plumbed,  and  that  sewer  gas  cannot  by  any  possibility 
escape  into  the  sick-room. 

The  swinging  of  doors  to  create  a  current  is  not  an  efficient  means  of  ven- 
tilation, as  it  agitates  the  air  of  the  room  without  purifying  it,  and  often  dis- 
turbs the  patient. 

A  draught  of  air  is  to  be  avoided ;  it  will  seldom  occur  that  the  air  of  the 
room  requires  to  be  so  speedily  changed  that  the  patient  need  be  exposed  to  a 
draught ;  never,  when  care  has  been  taken  to  provide  continuous  and  gradual 
ventilation. 

It  should  be  borne  in  mind  that  cold  air  is  not  necessarily  pure  air,  and  that 
ventilation  is  not  less  needed  in  winter  than  in  warm  weather. 

Sleep  is  a  great  necessity  to  the  sick.  If  a  well  person  slumbers  in  the  day- 
time, it  will  interfere  with  his  sound  repose  at  night,  but  with  the  sick  this  is 
generally  not  the  case.  The  more  they  sleep  the  more  favorable  are  the 
chances  for  their  recovery :  so  that  it  will  be  readily  seen  how  important  it 
is  to  avoid  noise  and  jar  in  the  sick-room,  especially  if  the  disease  is 
acute. 

Bear  in  mind  that  even  slight  noises,  as  the  rustling  of  garments,  the  creak- 
ing of  doors,  whispering,  or  noisy  footfalls,  may  be  sufficient  to  disturb  a  brain- 
that  is  rendered  sensitive  by  pain  or  wakefulness. 


APPENDIX.  295 

The  clothing  next  the  skin  should  be  changed  more  frequently  in  sickness 
than  in  health.  These  changes  must  be  quickly  and  deftly  made,  and  with  as 
little  disturbance  as  possible. 

Under  some  conditions  of  disease,  the  best  welfare  of  the  patient  is  accom- 
plished by  having  two  beds  in  the  room  instead  of  one. 

The  temperature  of  the  room  must  be  watched.  To  that  end  a  thermometer 
should  always  be  present,  and  easily  approached.  It  is  better  not  to  have  it 
directly  in  the  view  of  the  patient.  The  temperature  should  not  be  allowed  to 
vary  much  from  65°  F. ,  unless  the  doctor  otherwise  directs. 

Let  the  furniture  be  as  plain  and  as  free  from  upholstery  as  possible  ;  not 
many  pieces  are  required.  Movable  carpets  or  rugs  are  better  than  those  that 
are  permanently  laid.  Curtains  about  the  windows  are  out  of  place  in  a  sick- 
room :  so  are  flowering  plants  and  birds,  as  a  general  rule.  Florence  Night- 
ingale, however,  makes  an  exception  in  the  case  of  chronic  invalids,  and 
consents  to  the  comforting  influence  of  a  pet  bird  or  two. 

In  regard  to  the  admission  of  visitors  and  conversation,  much  will  depend 
upon  the  strength  of  the  patient  and  the  kind  of  sickness :  at  many  times  these 
are  to  be  forbidden,  as  having  a  disquieting  influence.  When  contagious 
disease  is  in  the  house,  the  sick-room  must  be  avoided  by  all  except  those 
who  have  the  care  of  the  patient,  and  those  having  this  care  should  avoid 
coming  in  contact  with  the  other  members  of  the  household,  especially  the 
children. 

Bear  in  mind  that  everything  brought  in  contact  with  the  sick  is  liable  to 
endanger  the  health  of  the  well. 

No  articles  in  use  by  the  invalid  should  be  removed  or  used  by  others  until 
thoroughly  disinfected  ;  the  dishes  and  spoons  should  be  put  in  boiling  water 
before  being  taken  from  the  room.  The  room  itself  should  be  fumigated  with 
sulphur  when  the  person  is  removed  from  it. 

Old  pieces  of  muslin,  etc.,  may  be  used  instead  of  handkerchiefs  to  receive 
the  poisonous  discharges  from  the  nose,  mouth,  and  throat.  These  can  be 
destroyed  by  fire,  and  thus  prevent  the  danger  of  conveying  the  disease  to 
others. 

"Taking  the  breath  "  and  kissing  should  be  avoided  by  those  in  attendance 
upon  the  case. 

The  bottles  of  medicine  and  other  reminders  of  illness  should,  as  far  as  con- 
venient, be  withdrawn  from  the  view  of  the  sick. 

Such  as  are  to  be  kept  always  at  hand,  should  be  arranged  in  an  orderly 
way  upon  a  tidily-covered  bed-side  table.  The  sight  of  a  siphon  bottle  of 
aerated  water  is  agreeable  to  most  patients  ;  that  may  be  kept  in  the  room, 
but  the  vessels  containing  milk,  drinking-water,  etc.,  should  be  kept  else- 
where. 

Disinfection. 

Filth  fosters  or  produces  certain  diseases ;  it  should,  therefore,  be  removed 
as  soon  as  possible.  When  it  is  difficult  to  remove  it,  disinfectants  come  into 


296  APPENDIX. 

play,  as  they  have  the  power  to  rob  it  of  some  of  its  disease-making  force. 
But  let  it  be  remembered  that  disinfection  is  not  cure  ;  it  is  not  a  substitute 
for  cleanliness  and  pure  air.  The  true  cure  is  the  removal  of  filth  ;  and  when 
our  homes  are  concerned  in  some  question  of  drainage  where  the  filth  is  out  of 
our  sight,  it  may  be  necessary  to  consult  and  employ  the  plumber  or  some 
other  artisan. 

In  times  gone  by,  it  was  the  custom  to  mask  bad  smells  by  burning  pastilcs, 
coffee,  cascarilla,  and  the  like.  These  are  not  now  much  used,  for  most  per- 
sons have  come  to  understand  that  the  fumes  thus  created  do  not  remove,  but 
simply  overpower  the  evil  odors. 

Chemistry  has  advanced  to  such  a  point  that  various  pungent  chemical  sub- 
stances, formerly  not  well  known,  can  be  furnished  at  small  cost,  and  these 
substances  have  the  power,  in  varying  degrees,  to  check  vile  odors.  Carbolic 
acid,  chloride  of  lime,  and  Labarraque's  solution  are  among  the  best  known  ol 
these,  but  there  are  also  certain  of  the  salts  of  iron,  and  zinc,  and  the  perman- 
ganate of  potash  that  may  be  used.  Sulphur  is  much  used  for  the  fumigation 
of  rooms  that  have  been  infected. 

Another  cheap  disinfectant  is  a  solution  of  chloride  of  lead.  It  is  inodorous, 
effective,  and  the  cost  is  small.  Take  half  a  drachm  of  the  nitrate  and  dissolve 
it  in  a  pint  or  more  of  boiling  water.  Dissolve  two  drachms  of  common  salt 
in  a  pail  or  bucket  of  water  ;  pour  the  two  solutions  together,  and  allow  the 
sediment  to  sink.  A  cloth  dipped  in  this  solution,  and  hung  up  in  a  room, 
will  correct  a  bad  odor  promptly,  or  if  the  solution  be  thrown  down  a  drain, 
or  upon  foul-smelling  refuse,  it  will  have  the  same  effect. 

The  room  to  be  purified  with  sulphur  should  be  made  as  tight  as  possible, 
so  that  no  fumes  can  escape,  either  by  window,  door,  or  chimney.  Put  three 
pounds  of  sulphur  in  an  iron  pot,  which  should  not  stand  upon  woodwork  or 
carpet,  lest  they  be  burned,  but  in  a  large  pan  of  ashes,  or  upon  a  layer  of 
bricks  ;  on  this  sulphur  pour  a  tablespoonful  of  alcohoL  This  is  then  set  on 
fire,  and  everybody  immediately  withdraws  from  the  room.  The  room  should 
remain  closed  ten  hours,  after  which  it  should  be  thoroughly  aired  before  it  is 
occupied,  for  the  fumes  of  the  sulphur  are  irritating  to  the  lungs. 

The  chemicals  above  mentioned  should  be  known  and  labeled  as  poisons. 
Many  persons  have  been  injured,  if  not  killed,  by  incautiously  or  ignorantly 
drinking  those  that  are  of  a  liquid  form. 

Heat  is  one  of  the  best,  if  not  the  best  disinfecting  agent  Articles  of  bed- 
ding and  furniture  that  cannot  well  be  treated  otherwise,  can  be  purified  by  a 
long  exposure  to  a  temperature  of  240°  F.  In  some  cities,  especially  in  Eng- 
land, furnaces  are  made  for  the  reception  of  bulky  articles  that  have  become 
infected. 

Fresh  pure  air  is  another  powerful  agent.  If  woven  fabrics,  clothing,  and 
the  like  are  for  a  long  time  aired  out  of  doors,  they  cease  to  be  infective  ; 
probably  by  the  enormous  dilution,  if  not  destruction,  of  the  elements  of 
danger. 


APPENDIX.  297 

Certain  diseases  are  "  catching;"  they  have  the  power  of  spreading  from  one 
person  to  another,  chiefly  by  the  particles  that  pass  off  from  the  body  of  the 
patient  Among  these  diseases  are  small-pox,  measles,  scarlet-fever,  and  diph- 
theria. The  articles  that  are  worn  or  used  by  the  patient  become  "  infected," 
and  they  should  be  disinfected  before  they  are  used  by  others.  As  a  rule,  of 
course,  a  doctor  will  be  called  in  to  attend  to  these  diseases.  When  that  is  so, 
follow  his  directions  as  to  disinfection,  as  well  as  every  other  part  of  the  treat- 
ment of  the  case.  For  substances  that  are  not  injured  by  being  washed,  a 
good  and  cheap  disinfectant  is  sulphate  of  zinc  ("white  vitriol")  and  common 
salt  dissolved  in  water,  boiling  hot  if  possible,  using  eight  tablespoonfuls  of 
the  zinc  and  four  of  salt  to  the  gallon  of  water.  This  is  useful  for  clothing, 
bed-linen,  towels,  handkerchiefs,  etc.  After  these  articles  have  lain  for  an 
hour  or  two  in  this  solution,  they  should  be  allowed  to  stand  in  boiling  water 
before  being  washed.  Infected  articles  that  are  of  little  value  should,  of 
course,  be  destroyed  by  fire. 

The  United  States  Treasury  Department  has  published  the  following  formula 
for  the  disinfection  of  the  rags  coining  from  Egypt :  "1.  Boiling  in  water  for 
two  hours  under  a  pressure  of  fifty  pounds  per  square  inch  ;  2.  Boiling  in 
water  for  four  hours  without  pressure  ;  or,  3.  Subjection  to  the  action  of  sul- 
phur fumes  for  six  hours,  burning  one  and  one-half  to  two  pounds  of  roll-brim- 
stone in  each  1,000  cubic  feet  of  space,  with  the  rags  well  scattered  upon 
racks."  Either  of  these  three  methods  is  accepted  as  sufficiently  thorough  to 
prevent  the  spreading  of  cholera  by  means  of  rags. 


Emergencies, 

"  The  readiness  is  all."— HAMLET. 

The  life  of  many  a  child  has  been  saved  by  the  fire-drill  in  schools,  and 
great  good  has  been  done  on  shipboard  by  a  drilling  of  the  crews. 

If  in  a  building  filled  with  smoke,  get  down  on  hands  and  knees  and  crawl 
to  door  or  window. 

In  a  cellar,  well,  or  vat,  where  carbonic  acid  clan  collect,  the  true  posture  is 
to  stand  erect.  If  a  candle,  on  being  lowered  into  a  suspected  place,  is  put 
out,  you  may  know  that  there  is  danger  to  human  life. 

Burns  and  Scalds. — The  secret  of  the  best  treatment  of  these  injuries  is  to 
exclude  the  air  from  the  wounded  surfaces.  When  they  are  slight,  and  the 
Bkin  is  not  destroyed  but  merely  blistered,  prevent  the  displacement  of  the 
ekin  as  much  as  possible*.  Let  the  blisters  be  punctured,  if  necessary,  to  let 
out  the  liquid,  and  then  keep  the  skin  in  place  by  cotton  cloth  or  lint,  wet 
with  a  solution  of  one  teaspoonful  of  carbolic  acid  in  a  quart  of  water,  or  a 
strong  solution  of  baking  soda.  The  cloth  should  be  kept  wet  constantly,  but 
do  not  irritate  the  wound  by  taking  off  the  dressing  too  often. 

Extensive  burns  are  much  worse  than  deep  burns.     In  the  former  case,  the 


298  APPENDIX. 

outlook  is  grave,  and  the  patient  will  probably  require  the  best  aid,  both 
medical  and  surgical,  of  some  physician. 

Scars  after  Burns.— If  a  bum  be  on  the  face,  neck,  or  near  a  joint,  it  is 
not  well  to  hasten  the  healing  process,  on  account  of  the  contraction  that 
always  takes  place  as  the  scar  is  formed. 

"  Fire  is  a  source  of  danger,  and  is  very  destructive  to  life  at  times.  Spon- 
taneous combustion  of  the  human  body  when  saturated  with  alcohol  is  a  myth, 
though  perhaps  the  alcoholized  body  does  burn  more  readily  than  one  free 
from  inflammable  fluid.  When  a  lady  is  on  fire,  she  should  not,  and  ought 
not  to  be  permitted  to  run  ;  that  fans  the  flames  amazingly.  She  must  be 
laid  down  and  rolled  up  in  the  nearest  woolen  article, — rug,  coat  or  blanket. 
Such  wrapping  up  in  a  non-inflammable  article  is  a  most  effective  method  of 
extinguishing  the  flames.  Immersion  in  water  is,  unfortunately,  rarely  prac- 
ticable. "—Pother gill. 

Illuminating  Gas  is  dangerous  in  two  ways.  If  it  escapes  into  a  tightly- 
closed  room  in  sufficient  quantities,  it  causes  the  death  of  the  inmates  by  suffo- 
cation, unless  some  one  from  without  discovers  the  perilous  situation.  If  not 
too  late,  remove  the  patient  into  fresh  air,  undo  the  clothing,  dash  cold  water 
on  the  face  and  neck,  and  employ  artificial  respiration,  as  in  drowning  (see 
p.  293).  Again  :  If  it  escapes  freely  into  an  apartment,  it  forms  an  explosive 
compound  by  mixing  with  the  air.  If  then  a  light  is  unguardedly  taken  into 
the  place,  an  explosion  that  may  be  destructive  to  life  will  result  Always  thor- 
oughly air  any  room  that  has  the  odor  of  escaping  gas  before  a  light  is  taken  in. 

Kerosene  is  the  cause  of  even  more  "accidents"  than  gas.  Too  much  care 
cannot  be  taken  in  its  use.  Buy  only  that  which  has  been  tested,  but  remem- 
ber that  not  all  that  are  marked  as  "safe"  are  truly  so.  If  a  responsible  oil- 
man certifies  that  the  oil  will  not  "flash"  under  140  degrees,  it  may  be 
regarded  as  safe  if  properly  used.  Lamps  should  be  filled  only  in  the  daytime. 
Never  attempt  to  fill  a  lamp  that  is  lighted,  and  never  put  kerosene  in  the 
stove  for  the  purpose  of  kindling  a  fire.  Very  small  lamps  are  dangerous,  as 
also  is  a  lamp  that  has  burned  a  long  time,  and  has  but  very  little  oil  in  it 

Frost-bites.— Keep  away  from  the  fire  and  in  a  cool  room.  Rub  the  nose 
or  other  part  that  has  been  "  bitten"  with  snow  or  ice- water  until  the  blood 
again  is  warmed  and  circulating  in  the  part.  Chilblains  should  not  be  brought 
to  the  fire  ;  if  the  skin  is  unbroken,  it  should  be  hardened  by  brushing  it  over 
with  alcohol  having  tannin  in  it 

Cuts.— These,  if  severe,  should  be  promptly  attended  by  a  physician,  but 
every  one  should  know  how  to  treat  small  wounds.  Learn  the  difference 
between  the  two  kinds  of  bleeding,  called  "  arterial "  and  "  venous. "  Arterial 
is  bright  red  and  comes  in  jets  (or  with  throbs  corresponding  to  the  pulse) ; 
venous  is  dark-colored  and  flows  continuously.  In  the  former,  press  on  that 
side  of  the  wound  nearer  to  the  heart ;  in  the  latter,  on  the  further  side.  Or, 
pressure  may  be  made  over  the  wound  itself  with  the  fingers ;  this  may  stop 
the  loss  of  blood  from  small  arteries  as  well  as  from  veins.  Loss  of  blood  from 


APPENDIX.  299 

arteries  is  apt  to  be  more  rapid  and  dangerous  than  that  from  veins,  and  when 
the  cut  vessel  is  a  large  one,  the  skill  of  the  surgeon  will  ordinarily  be  required 
in  order  to  close  the  bleeding  artery  permanently  and  securely. 

It  is  well,  in  every  household,  to  have,  in  some  handy  and  well-known 
place,  some  strips  of  old  muslin  and  some  lint,  or  oakum,  a  bandage  or  two 
and  some  adhesive  plaster,  a  soft  sponge,  and  needles  and  thread  in  a  basket 
or  box  by  themselves.  In  this  way,  valuable  time  may  be  saved  in  the 
staunching  of  blood,  flowing  in  consequence  of  some  accidental  cut  or  othei 
injury. 

Fits  OP  Convulsions. — These  may  be  trivial  or  grave.  If  it  is  a  young 
woman,  the  attack  is  probably  hysterical  and,  as  a  rule,  not  dangerous,  and  a 
sprinkle  of  cold  water  will  bring  relief.  If  the  patient  struggles  with  regular- 
ity of  movement,  and  there  is  bloody  froth  on  the  lips,  it  is  a  case  of  epilepsy, 
and  requires  a  physician's  attendance.  Meanwhile,  protect  the  head  from 
injury  by  putting  a  pillow  or  some  soft  article  beneath  it;  a  cork  intro- 
duced between  the  teeth  will  prevent  the  biting  of  the  tongue..  Prevent  the 
person  from  falling  or  injuring  himself,  but  do  not  attempt  to  forcibly  hold 
him  quist. 

In  children,  apply  cloths  dipped  in  water  to  the  head;  disturb  the 
child  as  little  as  possible;  do  not  use  a  warm  bath  until  directed  by  the 
doctor. 

Fainting. — This  occurs  when  the  blood  is  deficient  in  the  brain.  The  proper 
position,  therefore,  is  upon  the  back.  Let  the  winnow  be  opened  to  admit 
fresh  air ;  fanning,  and  the  sprinkling  of  water  are  useful.  If  the  clothing  about 
the  chest  is  tight,  let  it  be  loosened.  If  the  faint  occurs  at  church  or  some 
public  gathering,  remove  the  person  promptly  to  the  outer  air;  for  foul  air  is 
frequently  the  cause  of  the  trouble. 

Vertigo.— This  is  "  a  rush  of  blood  to  the  brain."  The  body  should  be 
placed  in  a  sitting  posture,  with  the  head  erect.  If  the  blood  escapes  into  the 
brain  by  reason  of  the  rupture  of  a  blood-vessel  within  it,  the  case  is  very 
grave,  and  the  physician  should  be  summoned  at  once.  Meanwhile,  let  the 
position  of  the  body  be  as  above  stated.  Apoplexy  is  known,  in  very  many 
cases,  by  the  helpless  condition  of  an  arm  or  leg,  or  both. 

Sunstroke  is  seldom  produced  in  this  climate  in  persons  who  have  not 
labored  too  hard.  Fatigue  and  sun -heat  are  commonly  the  joint  causes  of 
sudden  prostration  in  summer;  although  "heat-stroke"  may  occur  in  an 
artificially-heated  atmosphere,  without  exposure  to  the  sun.  In  the  tropics,  the 
least  possible  exertion  is  by  the  natives  put  forth  during  the  midday  hours.  On 
very  hot  days,  therefore,  avoid  fatigue  and  labor  in  the  open  air  as  much  as 
possible.  Keep  the  head  cool.  If  any  unusual,  dizzy  feeling  comes  on,  apply 
cold  water  to  the  head  and  neck.  If  a  person  falls  unconscious,  and  the  skin 
is  decidedly  hot  and  dry,  he  should  be  taken  to  a  cool  place.  If  the  face  and 
head  are  red  and  hot,  apply  ice-water  on  cloths.  If  pale,  give  stimulants 
gradually,  and  uae  cold  water  sparingly. 


300  APPENDIX. 

Shock  may  be  caused  by  a  fall  or  a  blow  upon  the  head  :>r  the  pit  of  the 
stomach.  It  is  known  by  slowing  of  the  pulse  and  respiration ;  the  face 
is  pale  and  the  skin  becomes  cool  The  head  should  be  placed  low,  some 
ammonia  in  water  be  given,  and  warmth  applied  to  the  surface  of  the 
body. 

The  Home  and  Health. 

The  location  of  the  house  should  be  airy,  dry,  and  sunny. 

A  certain  amount  of  elevation  is  necessary,  in  order  to  secure  proper  drain- 
age. Too  much  shade  must  not  fall  upon  the  house,  as  sunlight  is  very 
necessary  to  a  proper  degree  of  animal  vigor.  Young  children,  as  is  well  known, 
especially  profit  by  the  tonic  influence  of  sunlight. 

The  cellar  is  an  important  part  of  the  dwelling ;  therefore,  unless  care  be 
taken  for  its  ample  ventilation,  it  will  be  the  source  from  which  is  supplied 
much  of  the  air  breathed  in  the  upper  chambers  of  the  house.  If  the  cellar 
is  damp  the  house  is  liable  to  become  so,  and  if  vegetables  are  stored  in  the 
cellar,  an  especial  degree  of  care  is  needed  to  ventilate  it  thoroughly  and 
constantly. 

House  Drainage. — An  English  writer  has  stated  that  "the  most  im- 
portant part  of  the  house  is  the  drains. "  This,  no  doubt,  sounds  strangely  to 
the  ears  of  many,  who  have  been  brought  up  to  view  the  parlor  or  drawing- 
room  as  the  true  centre  of  the  house,  and  yet  it  is  no  foolish  saying,  when  we 
reflect  that  with  a  bad  system  of  drainage  to  a  house  every  dweller  therein 
stands  in  peril  of  several  forms  of  disease  that,  mild  as  the  cases  may  be,  are 
a  source  of  anxiety,  and  when  severe,  too  often  have  a  fatal  termination. 
Drain-diseases,  such  as  typhoid  fever,  dysentery,  diphtheria,  and  scarlet  fever, 
often  destroy  entire  families.  These  diseases  do  not  always  spring  upon  a  home 
through  defective  drainage,  but  when  they  do,  they  frequently  show  them- 
selves in  a  very  violent  form. 

Drainage  (as  applied  to  dwellings)  consists  in  conveying  away  from  the  house 
the  liquid  and  solid  impurities  that  would  otherwise  accumulate  in  or  near  the 
dwelling.  Waste  is  a  necessary  accompaniment  of  all  animal  life,  to  the  prepa- 
ration and  the  taking  of  food,  to  the  clothing  of  the  body,  to  bathing  and  other 
simple  acts  of  daily  life.  The  waste  material  of  houses  tends  to  decay  and  to 
become  offensive.  It  must,  therefore,  not  only  be  put  out  of  sight  and  smell, 
but  must  be  removed  so  far  away  that  it  cannot  return  in  the  form  of  danger- 
ous, invisible  gases  of  decomposition. 

The  best  house-drains  are  made  of  iron  or  glazed  earthenware,  carefully 
selected  and  well  laid.  The  joints  of  the  pipes  should  be  gas-tight.  The  soil- 
pipe  should  be  carried  up  to  and  through  the  roof.  All  the  waste-pipes  from 
basins,  etc.,  in  the  rooms  should  be  joined  in  a  gas-tight  manner  to  the  soil- 
pipe,  and  each  and  every  basin  and  other  fixture  should  have  a  separate  trap, 
is  a  trap  ?  It  is  a  device  that  is  designed  to  retain  a  certain  portion  of 


APPENDIX.  301 

the  water  running  through  it — called  the  "water-seal" — so  that  the  ascent  of 
air  or  gas,  from  the  drain  back  into  the  room,  is  prevented,  It  "  traps"  the 
sewer  gas  away  from  us.  Whenever  a  fixture  has  been  used  and  there  is  not, 
beyond  all  doubt,  a  sufficiency  of  water  to  fill  the  trap,  additional  water  should 
be  poured  in.  Traps  are  of  various  sizes,  and  of  an  infinite  variety  of  patterns 
and  patents,  and  must  vary  greatly  according  to  their  situation  ;  but  one  thing 
should  be  made  sure  of  in  their  use — namely,  that  they  hold  not  less  than  two 
inches  of  water  as  a  "  seal." 

There  is  at  almost  all  seasons  of  the  year  an  upward,  because  warmer,  cur- 
rent of  air  through  the  main  pipes.  It  is  therefore  better  to  have  a  fresh-air 
inlet  pipe  near  the  point  where  the  drain  leaves  the  house-wall.  This  helps 
to  prevent  the  unsealing  of  traps.  It  also  brings  about  a  purer  condition  of 
the  air  in  the  interior  of  the  system  of  pipes — so  useful  is  this  air-current 
through  the  soil-pipe  that  if  applied  there  is  little  danger  of  the  escape  of 
sewer  gas  into  the  living  rooms. 

"What  is  sewer  gas  or  sewer  air  ?  It  varies  greatly  in  different  places  and  at 
different  times.  It  is  not  a  definite  gas,  like  oxygen,  nitrogen,  etc.,  but  varies 
in  composition,  and  what  is  still  more  worthy  of  note,  it  varies  in  its 
dangerous  qualities.  It  is  not  always  offensive,  although  it  is  generally  so ; 
its  odor  has  been  described  as  being  "sweetish  and  sickish."  Its  danger- 
ous qualities  have  not  yet  been  determined  by  chemistry  or  the  microscope, 
but  one  practical  point  may  be  borne  in  mind — namely,  that  when  a  case  or 
cases  of  contagious  disease  occur  in  any  house  along  any  given  line  of  sewer 
pipes,  it  is  best  to  use  disinfectants  in  the  drainage  of  the  other  dwellings 
along  the  same  line  of  sewer.  Children  should  avoid  playing  over  or  around 
the  sewer-gratings  in  the  streets  at  all  times,  and  especially  when  scarlet  fever 
and  like  contagious  diseases  are  known  to  be  in  the  neighborhood  ;  for  the  exit 
of  sewer  air  at  these  points  is  always  very  free,  unless  it  be  directly  after  rainfall 

One  other  point  must  be  remembered — that  the  best-laid  system  of  house- 
plumbing  is  not  indestructible.  In  the  course  of  time,  defects  will  arise, 
breaks  will  occur  ;  for  this  reason  it  would  be  well  for  every  householder  to 
have  an  examination  made  at  intervals  of  every  joint  and  along  the  whole  line 
of  the  house  connection  with  the  sewer  or  drain. 

It  is  thought  by  many  that  sewer  gas  is  not  found  in  the  country  because 
there  are  no  sewers — they  have  been  misled  by  the  word.  If  the  words  "drain 
air"  or  "filth  gas"  had  been  adopted,  the  universal  production  of  this  inju- 
rious substance,  in  close  connection  with  every  abode  of  man,  wherever 
located,  might  have  been  better  understood.  In  country  houses  there  are, 
perhaps,  fewer  dangers  of  contamination  of  the  air  we  breathe  by  waste 
products,  because  there  are  fewer  water-closets,  wash-basins,  sinks,  etc.,  and 
the  rooms  are  less  exposed  to  impure  air. 

But  in  the  country  danger  is  apt  to  come  by  or  through  the  pollution  of  the 
water  supply.  The  well,  which  furnishes  that  cool  and  refreshing  draught,  is 
the  point  to  be  watched.  It  is  convenient  to  have  the  well  near  the  house, 


302  APPENDIX. 

because  when  snow  is  on  the  ground  and  the  weather  is  cold,  the  distance  te 
the  well  from  the  house  is  a  matter  of  no  small  moment.  Near  the  house 
must  be  the  stable  and  pens  for  animals — the  waste  from  the  house  goes  upon 
the  ground,  and  not  very  far  away  from  the  house — the  chamber  slops  and  the 
more  offensive  matters  go  into  a  pit,  which  must  not  be  too  distant.  The 
result  of  all  these  conditions  is  a  pollution  of  the  soil  at  all  these  points — a 
pollution  which  spreads  with  every  rainfall,  and  which,  sooner  or  later, 
reaches  the  well ;  yet  the  water  may  appear  as  pure  as  ever.  It  only  remain? 
to  have  the  suitable  disease-germ  lodged  in  this  polluted  territory  to  bring 
down  the  whole  household  with  a  fever.  This  is  the  kind  of  soil-pollution 
which  is  hard  to  cure,  and  which,  in  long-settled  countries,  causes  laws  to  bo 
enacted  requiring  all  vaults  for  the  reception  of  house  and  human  waste  to  be 
made  water-tight,  so  as  to  save  the  soil  from  its  poisoning  influence. 

This  is  the  kind  of  poisoning  which,  in  the  Dark  Ages,  caused  so  much 
unrighteous  persecution  of  the  innocent.  In  those  days,  no  care  whatever 
was  taken  in  the  towns,  high-walled,  crowded,  and  unsewered,  to  protect  the 
water  supply  from  pollution — as  a  result,  some  terrible  epidemic  of  fever  would 
arise.  Then  the  angry  populace  would,  in  their  ignorance,  cry  out :  "The 
Jews  have  poisoned  the  wells."  The  wells  were  poisoned,  no  doubt,  but  the 
Jew  was  no  more  worthy  of  blame  than  were  his  accusers.  Nevertheless,  the 
Jews  were  not  spared — they  were  robbed,  imprisoned,  executed. 

Drainage  in  the  city  is  a  comparatively  easy  problem  when  the  city's  sewers 
are  laid  in  the  streets.  In  the  country  it  is  more  difficult,  and  on  this  account 
the  fewer  fixtures  or  "modern  improvements"  there  are  in  the  house  the  bet- 
ter it  will  be.  There  should  be  no  less  care  within  the  country  house,  where 
waste-pipes  are  put  in,  than  in  the  city  house.  The  material  should  be  well 
selected,  tightly  joined,  and  properly  ventilated.  The  water-closet  should  be 
remote  from  the  house.  Earth-closets  are  better  than  the  ordinary  vaults — • 
house-waste  from  kitchen  and  laundry  should  be  taken  to  a  considerable  dis- 
tance from  the  house,  and  far  away  from  the  well,  and  either  deposited  in  a 
water-tight  cesspool  or  conveyed  away,  by  a  system  of  subsoil  drainage  tiles, 
arranged  so  as  to  fertilize  some  unoccupied  plot  of  ground. 

On  Going-  into  the  Country* 

To  spend  the  summer  in  the  country  would  be  the  choice  of  all  city-dwellers, 
whenever  their  purses  will  permit  of  it.  And  there  are  not  a  few  advantages 
in  such  a  course  ;  the  change  of  scene  is  good,  the  mountains  and  the  seaside 
give  a  purer  and  cooler  air — an  air  that  invigorates  and  aids  in  restful  sleep  at 
night,  so  different  from  the  midsummer  atmosphere  in  hot  cities.  There  are 
fewer  excitements  in  the  country  ;  we  do  not  "live  so  fast,"  and  there  is  full 
scope  for  healthful  life  and  activity  in  the  open  air,  with  the  green  and  blue 
of  nature  all  about  us,  instead  of  the  monotonous  walls  of  towering  houses. 

But  this  course,  pleasant  and  helpful  to  so  many,  is  not  without  its  danger, 


APPENDIX.  303 

Many  who  "go  away"  on  vacation  are  brought  home  sick  on  account  of  fever 
or  other  sickness  caused  by  defects  and  faults  of  drainage  existing  in  these 
temporary  summer  homes.  Scarcely  a  year  goes  by  that  one  or  more  summer 
resorts  have  not  gained  the  ill  name  of  being  the  hotbeds  of  typhoid  fever, 
dysentery,  and  the  like. 

In  view  of  this,  how  important  it  becomes  that  we  exercise  judgment,  and 
se-jk  skilled  advice  in  the  selection  of  our  summering  places. 

Again,  there  is  another  danger  that  must  not  be  overlooked.  Let  us  sup* 
pose  that  the  summer  vacation  has  passed  by  without  accident ;  that  we  return 
invigorated  by  the  experience,  and  that  the  home  in  the  city  has  been  empty 
and  closed  during  our  absence ;  what  has  happened  that  the  air  in  the  rooms 
newly  reopened  should  be  foul  and  stifling  ?  This  has  taken  place ;  the  water 
that  stands  in  the  traps  of  house  pipes,  and  shuts  off  gases  from  the  sewer, 
when  the  rooms  are  in  use  and  water  is  daily  entering  the  different  wash- 
basins, etc.,  has  during  our  absence  been  evaporated.  For  weeks,  perhaps, 
there  has  been  no  "water-seal"  in  the  traps,  and  the  ascent  of  sewer  air  has 
been  going  on  continuously,  so  that  not  only  is  the  air  utterly  unfit  to  live  in, 
but  all  the  curtains,  carpets,  and  other  absorbing  materials  have  become 
saturated  with  the  pollution  thus  allowed  to  enter.  Let  it  be  remembered 
that  when  a  sink,  etc.,  is  not  in  use,  it  is  gradually  losing  the  trap- water  by 
the  evaporation. 

What  is  the  remedy,  you  will  ask,  for  the  condition  of  things  caused  by 
closing  up  the  house,  as  above  stated  ?  To  this  the  reply  is,  that  the  house 
shouJa  irom  time  to  time  be  opened  and  aired,  and  water  should  be  poured 
down  each  and  every  sanitary  fixture,  in  sufficient  quantity  to  renew  the 
supply  of  water  in  the  trap  of  each. 

Experiments. 

Composition  of  Bone.— (Page  16,  par.  3.)— To  demonstrate  the  presence 
of  the  mineral  matter  in  bone,  obtain  a  sheep's  rib  or  any  other  long  bone. 
Clean  it  thoroughly  and  macerate  it  for  several  days  in  dilute  muriatic  acid 
(one  part  acid  to  eight  of  water).  The  length  of  time  required  will  depend 
upon  the  thickness  of  the  bone  ;  for  a  rib,  three  to  four  days  will  suffice.  The 
bone  will  now  be  found  quite  soft  and  pliable,  although  retaining  its  original 
shape,  and  may  readily  be  tied  into  a  knot.  The  specimen  can  be  preserved 
in  alcohol  for  an  indefinite  period. 

This  shows  that  it  is  the  mineral  matter  which  gives  firmness  and  hard- 
ness to  the  bones,  and  that  they  depend  for  elasticity  upon  the  animal  sub- 
stance. 

To  isolate  the  mineral  matter,  burn  a  long  bone  in  a  bright  fire,  which  con- 
sumes all  the  animal  substance,  leaving  the  mineral  matter  intact.  The  bone 
again  retains  its  shape  and  form  perfectly,  but  has  now  become  quite  brittle. 

We  see  by  this  that  it  is  requisite  to  have  both  animal  and  mineral  matter 
present  in  bone,  so  as  to  make  it  both  strong  and  elastic. 


304  APPENDIX. 

Structure  of  Bone. — (Page  17,  par.  5.) — Obtain  one  of  the  long  bones  of 
the  sheep  or  calf,  scrape  it  thoroughly  clean,  but  do  not  detach  the  cartilage 
covering  the  ends.  Saw  it  through  crosswise  in  the  middle  ;  then  saw  the 
upper  half  through  lengthwise.  (See  fig.  1,  page  17.) 

The  transverse  section  shows  the  compact,  hard  outer  layer,  enclosing  the 
soft  pulp  or  marrow. 

The  longitudinal  section  shows,  at  its  upper  end,  the  layer  of  cartilage,  its 
thickness  and  intimate  connection  with  the  bone ;  the  outer  layer  of  bone  here 
is  thinnest  and  gradually  increases  toward  the  middle  of  the  shaft,  where  it 
is  thickest ;  the  central  canal,  containing  the  marrow,  becomes  smaller  as  it 
approaches  the  head  of  the  bone,  where  it  is  lost  in  the  dense  network  of 
bony  structure.  The  latter  is  best  demonstrated  by  holding  the  cut  surface 
for  a  while  under  a  faucet,  so  as  to  wash  away  the  blood,  etc.,  contained  in  the 
meshes.  It  will  now  be  seen  that  these  meshes  are  composed  of  delicate  but 
strong  bony  partitions,  arranged  in  such  angles  to  the  outer  wall  and  to  them- 
selves, as  will  support  the  greatest  weight. 

Digestion. — a.  SALIVA. — (Page  111,  par.  17.) — The  chemical  action  of  saliva 
upon  boiled  starch  may  be  demonstrated  by  the  following  simple  experi- 
ments : 

1.  Prepare  a  thin  solution  of  boiled  starch ;  three  parts  of  starch  to  one 
hundred  parts  of  water ;  boil  for  a  few  minutes. 

2.  Obtain  a  fresh  quantity  of  saliva,  which  is  best  done  by  revolving  a  small 
pebble  in  the  mouta,  which  causes  a  copious  flow.    Collect  this  in  a  separate 
vessel. 

3.  Demonstrate  that  no  sugar  is  present  in  this  starch  solution.     Obtain 
from  a  druggist  an  ounce  or  two  of  "  Fehling's  solution  "  (this  is  a  solution  of 
sulphate  of  copper  and  of  certain  alkalies).     Sugar  has  the  power  of  changing 
the  sulphate  into  an  oxide  of  copper  which  is  reddish-brown.    Of  this  put  half 
a  teaspoonful  into  a  test  tube,  add  an  equal  quantity  of  the  starch  solution, 
and  let  come  to  a  boil  over  an  alcohol  lamp.     No  change  in  the  blue  color 
will  be  observed. 

4.  Demonstrate  that  the  saliva  does  not  contain  sugar  by  boiling  a  small 
quantity  with  an  equal  quantity  of  "Fehling's  solution,"  when  no  change  of 
the  blue  color  will  be  observed. 

5.  Now  in  a  third  test-tube  mix  a  quantity  of  the  starch  solution  with  one- 
third  its  volume  of  fresh  saliva,  and  set  aside  for  five  to  ten  minutes  in  a  warm 
place,  or  a  glass  of  warm  water  of  about  100°  F.     Then  take  of  this  again  a 
small  quantity  and  add  an  equal  part  of  "Fehling's  solution,"  shake  the  mix- 
ture and  boil.     As  soon  as  the  boiling  point  is  approached,  it  will  be  seen  that 
the  blue  color  disappears,  being  replaced  by  a  reddish-brown  color.    This 
demonstrates  the  presence  of  sugar  in  the  starch  solution,  produced  by  the 
action  of  the  saliva  added. 

6.  GASTRIC  JUICE.—  (Pag.  115-113,  par.  25-30.)— The  action  of  the  gastric 
juice  upon  the  albuminoids  can  be  readily  demonstrated  outside  of  the  body. 
For  this  it  is  necessary  to  prepare  a  solution  of  pepsin  and  a  solution  of  hydro- 
chloric acid.    The  first  of  these  may  be  made  in  one  of  two  ways.    The  sirn- 


APPENDIX.  305 

plest  of  these  is  to  obtain  some  pure  pepsin  from  the  druggist,  and  dissolve  of 
this  thirty  grains'  in  four  ounces  of  pure  glycerin  ;  the  other,  but  more  compli- 
cated way,  is  to  obtain  a  pig's  stomach,  dissect  off  the  mucous  membrane, 
mince  finely  and  add  six  ounces  of  glycerin,  set  aside  for  a  week  and  strain 
through  muslin.  The  solution  of  hydrochloric  acid  should  be  of  the  strength 
of  two  parts  per  thousand,  which  would  be  about  two  or  three  drops  of  the 
strong  acid  to  four  ounces  of  water. 

Demonstrate  that  neither  the  solution  of  pepsin  nor  the  hydrochloric  acid 
alone  have  the  power  to  digest  albuminoids. 

Prepare  three  test-tubes  as  follows  : 

1.  Into  one  put  about  a  teaspoonful  of  the  pepsin  solution,  and  add  a  small 
piece  of  the  white  of  a  hard-boiled  egg. 

2.  Into  the  second  test-tube  put  a  teaspoonful  of  the  dilute  hydrochloric 
acid,  and  add  again  a  small  piece  of  the  white  of  the  egg. 

3.  The  third  test-tube  fill  half  with  the  solution  of  acid,  add  half  a  teaspoon- 
ful of  the  pepsin  solution,  and  again  a  small  piece  of  the  egg. 

Now  set  these  three  tubes  aside  in  a  warm  place  for  a  few  hours,  or  until 
the  following  day,  when  you  will  be  able  to  demonstrate  that  in  the  first  two 
no  change  lias  taken  place,  while  the  white  of  egg  in  the  third  has  been 
entirely  dissolved. 

c.  BILE.— (Page  118,  par.  33.)— The  chief  function  of  the  bile  in  the  digestion 
of  food  is  the  emulsifying  of  fats. 

If  a  quantity  of  oil  is  shaken  up  with  an  equal  part  of  water  in  a  test-tube, 
the  two  will  not  mix.  But  if  we  substitute  bile  for  the  water,  and  shake 
thoroughly,  we  obtain  an  emulsion  which  will  separate  but  slowly  and  imper- 
fectly. 

The  bile  may  be  obtained  from  the  gall-bladder  of  the  ox  or  sheep  at  any 
butcher's  or  slaughter-house. 

d.  PANCREATIC  JUICE.—  (Page  119,  par.  34).—  To  obtain  the  pancreatic  juice, 
it  will  be  necessary  to  extract  it  from  a  fresh  pancreas  u  sweet-bread  "  (which 
may  be  bought  of  any  butcher),  by  means  of  either  water  or  glycerin.     Mince 
the  pancreas  finely  and  add  sufficient  of  either  of  these  liquids  to  cover  it,  set 
aside  for  a  day  and  strain  or  filter.     The  glycerin  extract  will  keep  for  a  long 
time  ;  the  watery  extract  soon  spoils. 

The  pancreatic  juice  has  a  digestive  action  on  all  the  food-stuffs. 

Its  action  upon  boiled  starch  may  be  demonstrated  by  repeating  the  experi- 
ments detailed  under  "Saliva,"  only  substituting  the  extract  of  the  pancreas 
for  the  saliva. 

Its  action  upon  albuminoids  is  shown  by  adding  to  a  few  teaspoonfuls  of 
the  pancreatic  extract  some  finely  minced  meat,  or  a  part  of  the  white  of  a 
boiled  egg.  But  as  the  action  of  the  pancreatic  juice  can  only  proceed  in  an 
alkaline  medium,  it  is  necessary  to  be  certain  of  the  alkalinity  of  the  fluid. 
This  is  best  done  by  adding  about  five  grains  of  carbonate  of  soda  (washing 
soda)  to  each  ounce  of  pancreatic  extract.  Set  the  test-tube  aside  in  a  warm 
place  for  a  few  hours,  when  the  meat  or  white  of  egg  wil*  be  found  entirely 
dissolved. 

Its  action  upon  fats  may  be  shown  by  shaking  up  in  a  test-tube  a  quantity 


306  APPENDIX. 

of  the  extract  with  an  equal  part  of  melted  lard  or  oil,  when  we  will  obtain  a 
very  perfect  emulsion. 

Coagulation  of  Blood.— (Pages  132,  133,  par.  9-11.)— The  coagulation  of 
blood  can  be  shown  to  a  class  with  but  little  trouble.  Obtain  from  a  butcher 
or  slaughter-house  about  a  pint  of  fresh  blood,  have  it  drawn  into  a  tin  can  or 
pail,  and  put  it  immediately  into  a  freezing  mixture  of  ice  and  salt.  If  it  be 
during  the  winter  and  freezing,  this  is  not  necessary,  as  freezing  suspends 
coagulation. 

Fill  a  glass  vessel  with  the  blood,  and  observe  the  different  steps  in  its 
coagulation.  In  about  two  to  three  minntes  it  becomes  viscid,  and  after  about 
five  to  ten  minutes  it  has  assumed  a  jelly-like  character,  so  that  the  vessel  can 
be  turned  over  without  spilling  its  contents.  Now  will  be  seen  on  the  surface 
of  the  jelly  a  few  drops  of  fluid,  which  rapidly  multiply,  so  that  soon  a  layer 
of  straw-colored  fluid  is  floating  on  the  surface.  This  fluid  increases,  and  the 
clot  contracts  more  and  more,  until  at  the  end  of  about  twelve  hours,  the 
process  is  complete,  and  we  have  a  firmly  contracted  clot  floating  in  a  clear 
straw-colored  fluid.  The  clot  is  composed  of  the  fibrin  and  corpuscles,  and 
the  fluid  is  the  serum,  colored  by  a  few  red  corpuscles. 

Changes  in  the  Color  of  the  Blood.— (Pages  135, 164,  par.  16, 19.)— The 
changes  produced  in  the  blood  by  the  atmosphere  are  of  easy  demonstration 
before  a  cltfss.  Obtain  from  a  butcher  some  freshly  *' whipped"  blood,  i.e., 
blood  rapidly  stirred  with  a  bundle  of  twigs  while  it  is  being  drawn  from  the 
animal.  This  removes  all  the  fibrin,  and  the  blood  no  longer  coagulates. 
Upon  standing  this  gradually  assumes  a  dark-brown  color. 

To  show  that  the  atmosphere,  or  rather  the  oxygen  in  the  atmosphere,  pro- 
duces the  bright  red  or  arterial  blood,  fill  a  pint  bottle  of  white  glass  about 
one-third  full  with  this  dark  blood,  and  shake  it  briskly ;  it  will  very  promptly 
assume  a  brighter  color.  The  same,  or  a  rather  better  result  may  be  obtained 
by  blowing  air  through  the  blood  by  means  of  a  glass  tnbe  inserted  into  the 
bottle  nearly  to  the  bottom.  After  having  blown  air  through  for  a  few  min- 
utes, the  blood  assumes  a  bright  scarlet  color.  Upon  standing  it  again  grad- 
ually grows  dark., 

The  Heart.— (Page  136,  par.  18-20.)— To  demonstrate  the  physiological 
anatomy  of  the  heart  will  require  some  dissecting,  and  a  little  more  care  and 
work  than  the  other  experiments,  but  the  teacher  will  be  fully  rewarded  by 
the  close  attention  and  great  interest  shown  by  the  pupils. 

Obtain  from  your  butcher  a  bullock's  heart  inclosed  in  ihe  pericardium  or 
"bag."  Instruct  him  to  cut  it  out  carefully  and  as  high  up  as  he  can,  so  as 
not  to  injure  it,  and  so  as  to  leave  of  the  large  blood-vessels  as  much  attached 
as  is  possible. 

Cut  away  all  the  fat  surrounding  the  heart  and  great  blood-vessels ;  cut  open 
the  pericardium  from  apex  to  base,  and  partly  away  from  the  latter,  so  as  to 
give  room  for  exposing  the  cavities  of  the  heart.  The  latter  should  be  opened 
by  two  incisions  along  the  septum  separating  the  right  from  the  left  heart. 
The  incision  should  run  from  apex  to  base,  laying  open  both  ventricle  and 


APPENDIX.  307 

auricle.     Cut  open  all  the  large  vessels  found  at  the  base,  into  the  cavities  to 
which  they  lead. 

Going  from  without  inward  observe  and  explain  the  different  parts  as  fol- 
lows : 

1.  THE  PERICARDIUM. — Note  its  structure  and  smooth,  shining  inner  sur- 
face.    Show  how  it  surrounds  the  heart,  and  how  it  is  attached  along  the  base 
and  great  blood-vessels. 

2.  GENERAL  STRUCTURE  OF  THE  HEART. — Show  the  thin-walled  auricles; 
the  difference  between  the  thickness  of  the  walls  of  the  ventricles ;  the  differ- 
ence in  structure  between  the  arteries  and  veins ;  demonstrate  the  two  coro- 
nary arteries  and  their  accompanying  veins. 

3.  RIGHT  AURICLE  AND  VENTRICLE. — Demonstrate  the  venae  cavae  and  their 
entrance  into  the  auricle ;    the  auriculo-ventricular  valves  between  the  two 
cavities  ;  the  structure,  attachment  and  action  of  the  valves ;  the  pulmonary 
artery. 

4.  LEFT  AURICLE  AND  VENTRICLE. — Demonstrate  the  pulmonary  veins  and 
their  entrance  into  the  auricle  ;  the  mitral  valve  between  auricle  and  ventricle  ; 
the  aortic  valve,  its  structure,  action  and  attachment ;  the  structure  and  great 
strength  of  the  aorta. 

Circulation.— (Pages  143-147)— The  circulation  of  the  blood  can  be  fairly 
well  illustrated  by  the  aid  of  a  "Davidson"  syringe,  some  rubber  tubing  and 
a  piece  of  glass  tubing. 

The  bulb  of  the  syringe  represents  the  heart,  the  elastic  tubing  the  arteries, 
and  the  fine  glass  tubing  the  capillaries. 

Attach  the  rubber  tubing  to  the  smallest  nozzle  of  the  syringe  (the  tubing 
should  be  highly  elastic,  the  black  kind  is  the  best ;  it  should  be  about  one- 
fourth  inch  diameter),  place  the  other  end  of  the  syringe  in  a  vessel  filled 
with  water. 

Upon  compressing  the  bulb  of  the  syringe,  the  water  will  be  seen  to  issue 
from  the  tubing  in  jets  corresponding  with  the  compressions  of  the  bulb,  but  a 
little  retarded  ;  placing  the  finger  on  the  tubing  but  little  expansion  will  be 
felt.  Now  into  the  rubber  tube  insert  the  glass  tube,  which  should  be  about 
two  feet  long  and  be  drawn  out  to  a  fine  point.  Compressing  again  the  bulb 
of  the  syringe,  the  water  will  be  seen  to  issue  from  the  glass  point  in  a  con- 
tinuous stream,  and  not  in  an  interrupted  one,  as  from  the  rubber  end. 

The  explanation  of  this  is  as  follows  :  During  each  compression  of  the  bulb, 
the  water  expands  the  rubber  tubing  because  its  outflow  is  considerably 
lessened  by  the  resistance  of  the  unyielding  glass-tube  and  its  much-narrowed 
end,  and  during  the  interval  of  two  compressions,  during  which  the  bulb  fills 
again,  the  rubber  tubing  contracts  upon  its  contents  and  slowly  expels  it.  If 
now  the  compressions  of  the  bulb  are  so  timed  that  the  rubber  tubing  is  kept 
stretched,  the  flow  from  the  glass-end  will  be  continuous.  The  finger  on  the 
tubing  will  now  feel  each  stroke  of  the  syringe  in  the  decided  expansion  of 
the  rubber. 

Applied  to  the  circulation  of  the  blood,  this  experiment  shows  the  following  : 

The  power  of  the  hand  together  with  the  bulb  of  the  syringe  represent  the 


308  APPENDIX. 

heart,  which,  with  each  contraction,  sends  its  contents  forth  into  the  arteries. 
These  are  well  represented  by  the  elastic  tubing,  as  they,  in  reality,  are  nothing 
more  than  that.  During  the  systole  of  the  heart  (the  compression  of  the  bulb), 
they  are  distended  to  their  full  capacity ;  during  the  diastole  of  the  heart 
(represented  by  the  passive  filling  of  the  bulb),  they  contract  upon  their  con- 
tents and  send  it  forward  toward  the  capillaries  and  veins.  The  latter  are 
represented  by  the  glass-tubing,  from  which  we  have  seen  the  water  issue  in  a 
continuous  stream.  In  the  capillaries  and  veins  the  blood  flows  in  a  continu- 
ous stream,  due  to  the  fact  that  the  force  of  the  heart's  action  is  gradually  lost 
in  expanding  the  arteries,  and  is  felt  less  and  less  the  farther  they  are  removed 
from  the  heart ;  the  arteries  becoming  smaller  and  smaller,  the  intermittency 
of  the  flow  is  lost  when  the  capillaries  are  reached. 

The  expansion  which  the  finger  feels  when  placed  upon  the  rubber  tubing 
represents  the  pulse,  which  is  the  maximum  distension  of  the  artery  at 
that  point. 

The  Lungs — Respiration.— (Pages  154-164.)— Obtain  from  your  butcher  a 
pair  of  sheep's  or  calf's  lungs  ;  they  should  be  cut  out  with  great  care,  so  as 
not  to  be  injured  in  any  part.  Insert  the  nozzle  of  a  pair  of  bellows  into  the 
trachea  and  tie  it  securely ;  then  inflate  the  lungs  fully,  and  tie  the  trachea 
just  below  the  point  of  the  nozzle  very  securely,  so  that  no  air  escapes.  Now 
hang  the  lungs  up  to  dry.  If  there  is  no  hole  in  any  part  of  them,  they  will 
retain  the  air  sufficiently  long  to  allow  the  air-oells  to  dry  in  this  distended 
state.  During  the  drying  the  lungs  will  shrink  somewhat,  but  that  will  not 
interfere  with  the  demonstration  of  the  specimen.  When  thoroughly  dry,  cut 
through  both  lungs  lengthwise  (see  fig.  44,  page  157)  with  a  long,  sharp  knife. 
You  will  then  obtain  a  very  interesting  and  valuable  specimen,  which  will 
keep  for  a  long  time  if  protected  from  dust.  It  shows  the  trachea  and  its 
structure,  bronchi  and  their  subdivision,  and  the  terminal  air-cells. 

The  presence  of  carbonic  acid  gas  in  the  expired  air  may  be  demonstrated 
by  blowing  air  through  some  perfectly  clear  lime  water,  by  means  of  a  glass- 
tube.  Carbonic  acid  gas  produces  a  chemical  change  in  the  lime  contained  in 
the  water,  transforming  it  into  carbonate  of  lime,  which  is  insoluble  in  water. 
After  the  air  has  been  blown  through  for  a  few  minutes,  the  water  becomes 
turbid,  and  after  a  longer  time,  milky.  Upon  standing,  this  milkiness  sub- 
sides to  the  bottom  in  the  form  of  a  fine  powder,  carbonate  of  lime. 


APPENDIX. 


309 


EXERCISES    FOR    HOME    GYMNASTICS. 

(SEE  PAGE  43.) 


FIG.  1. — POSITION  TOR  EXERCISING. 


FIG.  2. — To  DEVELOP  MUSCLES  ACROSS 
THE  UPPER  BACK. 


PIG.  3.— To  DEVELOP  FRONT  ARM,  CHEST, 
ABDOMEN,  FRONT  LEG. 


FIG.  4.— To  DEVELOP  LOWER  BACK 
AND  MIDDLE  BACK. 


NOTE.— The  cuts  of  the  above  illustrations  were  kindly  furnished  by  the  Narragaiisett 
Machine  Company,  manufacturers  of  the  apparatus,  Providence,  R.  L 


310 


APPENDIX. 


FIQ.  5.— To  DEVELOP  BACK  UPPER  ARM. 


Fia.  6.— To  DEVELOP  CHEST  MUSCLE? 
AND  FRONV  ARM. 


Fio.  7.— To  DEVELOP  SIDE-WAIST 
MUSCLES. 


FIG.  8.— To  DEVELOP  UPPER  AKP 
LOWER  BACK,  SHOULDER,  BACK 
ABM  AND  BACK  LEO. 


APPENDIX. 


311 


g.—To  DEVELOP  ABDOMEN  ;  TO  DEEPEN  THE  THORAX. 


FlG.  10.— TO  WIDEN  THE  THORAX   AND  DEVELOP  THE  SlDES  OP  "WAIST. 


Fl6.  11.— TO  DEVELOP  THE  ABDOMINAL  MUSCLES  AND  THE  MUSCLES  CP  UPPER 


GLOSSARY, 


AB-DO'MEN  (Latin  abdo,  to  conceal).     The  largest  cavity  of  the  body,  contain- 

ing  the  liver,  stomach,  intestines,  etc. ;  the  belly. 

AB-SOR'BENTS  (L.  ab  and  sorbeot  to  suck  up).     The  vessels  which  take  part  in 
.    the  process  of  absorption. 

AB-SORP'TION.     The  process  of  sucking  up  fluids  by  means  of  an  animal  mem- 
brane. 
AC-COM-MO-DA;TION  of  the  Eye.     The  alteration  in  the  shape  of  the  crystalline 

lens,  which  accommodates  or  adjusts  the  eye  for  near  and  remote  vision. 
AC'ID,  LACTIC  (L.  lac,  milk).     The  acid  ingredient  of  sour  milk ;  the  gastric 

juice  also  contains  it. 
AL-BU'MEN,  or  Albumin  (L.  albus,  white).     An  animal  substance  resembling 

white  of  egg. 
AL-BU'MI-NOSE  (from  albumen}.     A  soluble  animal  substance  produced  in  the 

stomach  by  the  digestion  of  the  albuminoid  substances. 

AL-BU'MIN-OID  substances.     A  class  of  proximate  principles  resembling  albu- 
men ;  they  may  be  derived  from  either  the  animal  or  vegetable  kingdoms. 
AI/I-MENT  (L.  alo,  to  nourish).     That  which  affords  nourishment;  food. 
AL-I-MENT'ARY  CA-NAL  (from  aliment).    A  long  tube  in  which  the  food  is 

digested,  or  prepared  for  reception  into  the  system. 
AN-.ES-THET'ICS  (Greek,  av,  an,  without,  aiffdqoia,  aisthesia,  feeling).    Those 

medicinal  agents  which  prevent  the  feeling  of  pain,  such  as  chloroform, 

laughing-gas,  etc. 
AN-I-MAL'CTJLE  (L.  animaVculum,  a  small  animal).   Applied  to  animals  which 

can  only  be  seen  with  the  aid  of  the  microscope.     Animalculum  (plural, 

animalcula)  is  used  with  the  same  meaning. 
A-OR'TA  (Gr.  dopreopai,  aorteomai,  to  be  lifted  up).    The  largest  artery  of  the 

body,  and  main  trunk  of  all  the  arteries.     It  arises  from  the  left  ventricle 

of  the  heart.     The  name  was  first  applied  to  the  two  large  branches  of  the 

trachea,  which  appear  to  be  lifted  up  by  the  heart 
A'QUE-OUS  HUMOR  (L.  aqua,  water).     A  few  drops  of  watery  colorless  fluid 

occupying  the  space  between  the  cornea  and  crystalline  lens. 
A-RACH'NOID  MEM'BRANE  (Gr.  dpd^vrj,  arachne,  a  cobweb,  and  eifoc,  eidos, 


GLOSSARY.  313 

like).     An  extremely  thin  covering  of  the  brain  and  spinal  cord.     It  lies 

between  the  dura  mater  and  the  pia  mater. 

AR'BOR  VI'T^E  (L.).     Literally,  "the  tree  of  life;"  a  name  given  to  the  pecu- 
liar appearance  presented  by  a  section  of  the  cerebellum. 
AR'TER-Y  (Gr.  drip,  aer,  air,  and  rr/peiv,  terein,  to  contain).    A  vessel  by  which 

blood  is  conveyed  away  from  the  heart.     It  was  supposed  by  the  ancients  to 

contain  air ;  hence,  the  name. 
AR-TIOU-LA'TION  (L.  articulo,  to  form  a  joint).     The  more  or  less  movable 

union  of  bones,  etc. ;  a  joint. 
A-RYT'E-NOID  CAR'TI-LA-GES  (Gr.  dpvTatva,  arutaina,  a  pitcher).     Two  small 

cartilages  of  the  larynx,  resembling  the  mouth  of  a  pitcher. 
AS-SIM-I-LA'TION  (L.  ad,  to,  and  similis,  like).     The  conversion  of  food  into 

living  tissue. 

ATJ-DI'TION  (L.  audio,  to  hear).     The  act  of  hearing  sounds. 
AU'DI-TO-RY  NERVE.     One  of  the  cranial  nerves  ;  it  is  the  special  nerve  of 

hearing. 

AU'RI-CLE  (L.  auris,  the  ear).    A  cavity  of  the  heart 
BAR'I-TONE  (Gr.  (3apvf,  barus,  heavy,  and  rovof,  tonos,  tone).     A  variety  of 

male  voice  between  the  bass  and  tenor. 
BEL- LA-DON' NA  (It.  beautiful  lady).     A  vegetable  narcotic  poison.     It  has 

the  property  of  enlarging  the  pupil,  and  thus  increasing  the  brilliancy  of  the 

eye ;  so  called  from  its  use  by  Italian  ladies. 
BI-CUS'PID  (L.  bi,  two,  and  cwpis,  prominence).     The  name  of  the  fourth  and 

fifth  teeth  on  each  side  of  the  jaw;  possessing  two  prominences. 
BILE.     The  gall,  or  peculiar  secretion  of  the  liver;  a  viscid,  yellowish  fluid, 

and  very  bitter  to  the  taste. 
BRONCH'I  (Gr.  Ppfyxos,  brogchos,  the  windpipe).    The  two  first  divisions  or 

branches  of  the  trachea ;  one  enters  each  lung. 

BRONCH'I- AL  TUBES.    The  smaller  branches  of  the  trachea  within  the  sub- 
stance of  the  lungs,  terminating  in  the  air-cells. 
BRONCH-I'TIS  (from  bronchia,  and  ttis,  a  suffix  signifying  inflammation).     An 

inflammation  of  the  larger    bronchial   tubes;    a    "cold"    affecting    the 

lungs. 

CAL-CA'RE-OUS  (L.  calx,  lime).  Containing  lime. 
CA-NAL'  (L. ).  In  the  body,  any  tube  or  passage. 
CA-NINE'  (L.  canis,  a  dog).  Name  given  to  the  third  tooth  on  each  side  of 

the  jaw;  in  the  upper  jaw  it  is  also  known  as  the  eye-tooth,  pointed  like 

the  tusks  of  a  dog. 
CAP'IL-LA-RY  (L.  capil'lus,  a  hair,  capilla'ris,  hair-like).     The  name  of  the 

extremely  minute  blood-vessels  which  connect  the  arteries  with  the  veins. 
CAR'BON  DIOX-IDE  (C08).     Chemical  name  for  carbonic  acid  gas. 
CAR-BON'IO  A'onx     The  gas  which  is  present  in  the  air  expired  from  the 

lungs ;  a  waste  product  of  the  animal  kingdom,  and  a  food  of  the  vegetable 

kingdom. 


314  GLOSSARY. 

CAR'DI-AC  (Gr.  Kapfaa,  cardia,  the  heart).  The  cardiac  orifice  of  the  stomach 
is  the  upper  one,  and  is  near  the  heart  j  hence  its  name. 

CAR-NIV'O-ROUS  (L.  ca'ro,  flesh,  and  vc/ro,  to  devour).     Subsisting  upon  flesh. 

CA-ROT'ID  AR-TE-RY.  The  large  artery  of  the  neck,  supplying  the  head  and 
brain. 

CAR'TI-LAGE.  A  solid  but  flexible  material,  forming  a  part  of  the  joints,  air- 
passages,  nostrils,  etc.;  gristle. 

CA'SE-INE  (L.  ca'seus,  cheese).  The  albuminoid  substance  of  milk,  it  forms 
the  basis  of  cheese. 

CER-E-BEI/LTJM  (diminutive  for  cerebrum,  the  brain).  The  little  brain,  situ- 
ated beneath  the  posterior  third  of  the  cerebrum. 

CER'E-BRUM  (L. ).  The  brain  proper,  occupying  the  entire  upper  portion  of 
the  skull.  It  is  nearly  divided  into  two  equal  parts,  called  "  hemispheres," 
by  a  cleft  extending  from  before  backward. 

CHO'ROID  (Gr.  x°Plov>  chorion,  a  membrane  or  covering).  The  middle  tunic 
or  coat  of  the  eyeball. 

CHYLE  (Gr.  xv^°C>  chulos,  juice).  The  milk-like  fluid  formed  by  the  digestion 
of  fatty  articles  of  food  in  the  intestines. 

CHYME  (Gr.  xvf*<>?>  chumos,  juice).  The  pulpy  liquid  formed  by  digestion 
within  the  stomach. 

CII/I-A  (pL  of  cil'i-um,  an  eyelash).  Minute,  vibratile,  hair-like  processes 
found  upon  the  cells  of  the  air-passages,  and  other  parts  that  are  habitually 
moist. 

CIR-CU-LA'TION  (L.  cirtculust  a  ring).  The  circuit,  or  course  of  the  blood 
through  the  blood-vessels  of  the  body,  from  the  heart  to  the  arteries,  through 
the  capillaries  into  the  veins  and  from  the  veins  back  to  the  heart. 

CO-AG-U-LA'TION  (L.  coacfulo,  to  curdle).  Applied  to  the  process  by  which 
the  blood  clots  or  solidifies. 

COCH'LE-A  (L.  coch'lea,  a  snail-shell).    The  spiral  cavity  of  the  internal  ear. 

CONCH' A  (Gr.  KOVXV,  (Iconche,  a  mussel-shell).  The  external  shell-shaped  por- 
tion of  the  external  ear. 

CON-JTJNOTI'VA  (L.  con  an&jun'go,  to  join  together.  A  thin  layer  of  mucous 
membrane  which  lines  the  eyelids  and  covers  the  front  of  the  eyeball; 
thus  joining  the  latter  to  the  lids. 

CON-TRAOTIL'I-TY  (L.  con  and  tra'Tw,  to  draw  together).  The  property 
of  muscle  which  enables  it  to  contract,  or  draw  its  extremities  closer  to- 
gether. 

CON-VO-LIT'TIONS  (L.  con  and  wVvo,  to  roll  together).  The  tortuous  foldings 
of  the  external  surface  of  the  brain. 

CON-VUL'SION  (L.  conveVlo,  to  pull  together).  A  more  or  less  violent  agita- 
tion of  the  limbs  or  body. 

COR'NE-A  (L.  cor'nuy  a  horn).  The  transparent,  horn-like  substance  which 
covers  the  anterior  fifth  of  the  eyeball. 

COR'PUS-CLES,  BLOOD  (L.  dim.  of  corpus,  a  body).   The  small  bi-concave  disks 


GLOSS  ART.  315 

which  give  to  the  blood  its  red  color;  the  white  corpuscles  are  globular  and 

larger. 
COS-MBT'IC  (Gr.  JCO<T^«,  Icosmeo,  to  adorn).      Beautifying ;  applied  to  articles 

which  are  supposed  to  increase  the  beauty  of  the  skin,  etc. 
CRA'NI-AL  (L.  era'  nium,  the  skull).     Pertaining  to  the  skull     The  nerves 

which  arise  from  the  brain  are  called  cranial  nerves. 
CRI'COID  (Gr.  «p//cof,  Jcri'kos,  a  ring).     A  cartilage  of  the  larynx  resembling 

a  seal-ring  in  shape. 
CRYS'TAL-LINE  LENS  (L.  crystal'lum,  a  crystal).     One  of  the  so-called  humors 

of  the  eye  ;  a  double  convex  body  situated  in  the  front  part  of  the  eyebalL 
CU'TI-CLE  (L.  dim.  of  cu'tis,  the  skin).      The  scarf-skin ;   also  called  the 

epidermis. 
CU'TIS  (L.,  skin  or  hide).     The  true  skin,  lying  beneath  the  cuticle;  also 

called  the  deijmis. 

DE-CUS-SA'TION  (L.  decusfsis,  the  Roman  numeral  ten,  X).    A  reciprocal  cross- 
ing of  fibres  from  side  to  side. 
DI'A-PHRAGM  (Gr.  diafypdaau,  diaphrasso,  to  divide  by  a  partition).     A  large, 

thin  muscle  which  separates  the  cavity  of  the  chest  from  the  abdomen ;  a 

muscle  of  respiration. 
DIF-FUS'ION  OF  GASES.      The  power  of  gases  to  become  intimately  mingled, 

without  reference  to  the  force  of  gravity. 
DUCT  (L.  du'co,  to  lead).    A  narrow  tube ;  the  thoracic  duct  is  the  main  trunk 

of  the  absorbent  vessels. 
DU-O-DE'NUM  (L.  duode'ni,  twelve).    The  first  division  of  the  small  intestines, 

about  twelve  fingers-breadth  long. 
DU'IIA  MA'TER  (L. ).     Literally,  the  hard  mother;  the  tough  membrane  which 

envelops  the  brain. 
DYS-PEP'SI-A  (Gr.  <fof,  dus,  difficult,  and  Trenrw,  pepto,  to  digest).    Difficult  01 

painful  digestion  ;  a  disordered  condition  of  the  stomach. 
E-MUL'SION  (L.  emul'geo,  to  milk).     Oil  in  a  finely  divided  state  suspended 

in  water. 

EN-AM'EL  (Fr.  email).    The  dense  material  which  covers  the  crown  of  the  tooth. 
ENDOCARDIUM  (Gr.  evSo,  endo,  within,  and  /capita,  kardia,  the  heart.    The 

lining  membrane  of  the  heart. 
EN'ER-GY,  Specific,  of  a  Nerve.     When  a  nerve  of  special  sense  is  excited, 

whatever   be    the   cause,   the    sensation  experienced  is  that  peculiar  to 

the  nerve ;  this  is  said  to  be  the  law  of  the  specific  energy  of  the  nerves. 
EP-I-GLOT'TIS  (Gr.  Im,  epi,  upon,  and  yAwrrjf,  glottis,  the  entrance  to  the 

windpipe).      A  leaf-shaped  piece  of  cartilage  which  covers  the  top  of  the 

larynx  during  the  act  of  swallowing. 
EX-CRE'TION  (L.  excer'no,  to  separate).     The  separation  from  the  blood  of  the 

waste  particles  of  the  body ;  also  the  materials  excreted. 
EX-PI-RA'TION  (L.  exyritro,  to  breathe  out).    The  act  of  forcing  air  out  of  tjie 

lungs, 


31 G  GLOSSARY. 

EX-TEN'SION  (L.  ex,  out,  and  ten' do,  to  stretch).  The  act  of  restoring  a  limb, 
etc.,  to  its  natural  position  after  it  has  been  flexed,  or  bent;  the  opposite  of 
Flexion. 

FE-NES'TRA  (L. ).  Literally,  a  window ;  the  opening  between  the  middle  and 
internal  ear. 

FI'BRINE  (L.  fi'bra,  a  fibre).  An  albuminoid  substance  found  in  the  blood ;  in 
coagulating  it  assumes  a  fibrous  form. 

FLEX'ION  (L.  flecto,  to  bend).     The  act  of  bending  a  limb,  etc. 

FOL'LI-CLE  (L.  dim.  offol'lis,  a  bag).  A  little  pouch  or  depression  in  a  mem- 
brane ;  it  has  generally  a  secretory  function. 

FUN'GOUS  GROWTHS  (L.  fun'gus,  a  mushroom).     A  low  grade  of  vegetable  life. 

GAN'GLI-ON  (Gr.  ydvyMov,  ganglion,  a  knot).  A  knot-like  swelling  in  the 
course  of  a  nerve  ;  a  smaller  nerve-centre. 

GAS'TRIC  (Gr.  yaanjp,  gaster,  stomach).     Pertaining  to  the  stomach. 

GLAND  (L.  glans,  an  acorn).  An  organ  consisting  of  follicles  and  ducts,  with 
numerous  blood-vessels  interwoven  ;  it  separates  some  particular  fluid  from 
the  blood. 

GLOS'SO-PHAR-YN-GE'AL  NERVE  (Gr.  yhtioca,  glossa,  the  tongue,  and  ^apuyf, 
pharugx,t}ie  throat).  The  nerve  of  taste  supplying  the  posterior  third  of  the 
tongue  ;  it  also  supplies  the  throat. 

GLU'TEN  (L. ).     Literally,  glue  ;  the  glutinous  albuminoid  ingredient  of  wheat. 

GRAN'ULE  (L.  dim.  of  gra'num,  a  grain).    A  little  grain  ;  a  microscopic  object 

GTJS-TA'TION  (L.  gusto,  to  taste).     The  sense  of  taste. 

GUS'TA-TO-RY  NERVE.  The  nerve  of  taste  supplying  the  front  part  of  the 
tongue,  a  branch  of  the  "fifth"  pair. 

HEM'OR-RHAGE  (Gr.  uipa,  hai'ma,  blood,  and  prjywpt,  regnumi,  to  burst). 
Bleeding,  or  the  loss  of  blood. 

HEM-I-PLE'GIA  (Gr.  rjntavs,  hemisus,  half,  and  Trhrjaow,  plesso,  to  strike). 
Paralysis,  or  loss  of  power,  affecting  one  side  of  the  body. 

HEM'I-SPHERES  (Gr.  c<palpa,  sphaira,  a  sphere).  Half  a  sphere,  the  latera 
halves  of  the  cerebrum,  or  brain  proper. 

HE-PAT'IC  (Gr.  fjirap,  hcpar,  the  liver).     Pertaining  to  the  liver. 

HER-BIV'O-ROUS  (L.  her'ba,  an  herb,  and  vo'ro,  to  devour).  Applied  to 
animals  that  subsist  upon  vegetable  food. 

HU'MOR  (L. ).    Moisture  :   the  humors  are  transparent  contents  of  the  eyeball. 

HY-DRO-PHO'BI-A  (Gr.  vSop,  hudor,  water,  and  0o.5t'w,  phobeo,  to  fear).  A  dis- 
ease caused  by  the  bite  of  a  rabid  dog  or  other  animal.  In  a  person  affected 
with  it,  convulsions  are  occasioned  by  the  sight  of  a  glittering  object,  like 
water,  by  the  sound  of  running  water,  and  by  almost  any  external  impres- 
sion. 

HY'GI-ENE  (Gr.  vyieia,  hugieia,  health).  The  art  of  preserving  health  and 
preventing  disease. 

HY'PER-O'PI-A.  Abbreviated  from  HY'PER-MET-RO'PI-A  (Gr.  bnep,  huper,  be- 
yond, perpov,  metron,  the  measure,  and  oty,  ops,  the  eye).  A  defect  of  vision 


GLOSSARY.  317 

dependent  upon  a  too  short  eyeball  ;  so  called  because  the  rays  of  light  are 

brought  to  a  focus  at  a  point  behind  the  retina  ;  the  true  "far  sight." 
IN-CI'SOR  (L.  inci'do,  to  cut).     Applied  to  the  four  front  teeth  of  both  jaws, 

which  have  sharp  cutting  edges. 

IN'CUS  (L.  ).     An  anvil  ;  the  name  of  one  of  the  bones  of  the  middle  ear. 
IN-SAL-I-VA'TION  (L.'  in,  and  sali'va,  the  fluid  of  the  mouth).     The  mingling 

of  the  saliva  with  the  food  during  the  act  of  chewing. 
IN-SPI-RA'TION  (L.  in,  and  spi'ro,  to  breathe).     The  act  of  drawing  in  the 

breath. 
IN-TEG'U-MENT  (L.  in,  and  te'go,  to  cover).     The  skin,  or  outer  covering  of  the 

body. 
IN-TES'TINE  (L.  in'tus,  within).     The  part  of  the  alimentary  canal  which  i&. 

continuous  with  the  lower  end  of  the  stomach  ;  also  called  the  intestines,  or 

the  bowels. 
PRIS  (L.  tfris,   the  rainbow).     The  thin  muscular  ring  which  lies  between  the 

cornea  and  crystalline  lens,  and  which  gives  the  eye  its  brown,  blue,  or 

other  color. 
JU'GU-LAR  (L.  ju'gulum,  the  throat).     The  name  of  the  large  veins  which  run 

along  the  front  of  the  neck. 
LAB'Y-RINTH  (Gr.^aj3vptv6o^,  Idburin'thos,  a  building  with  many  winding  pas- 

sages).    The  very  tortuous  cavity  of  the  inner  ear,  comprising  the  vestibule, 

semicircular  canals,  and  the  cochlea. 
LACH'RY-MAL  APPARATUS  (L.  lach'ryma,  a  tear).  The  organs  for  forming  and 

conveying  away  the  tears. 
LAC'TE-ALS  (L.  lac,  lac'tis,  milk).     The  absorbent  vessels  of  the  small  intes- 

tines ;  during  digestion  they  are  filled  with  chyle,  which  has  a  milky  appear- 


LA-RYN'GO-SCOPE (Gr.  ylapvyf,  larunx,  the  larynx,  and  GKoireu,  skopeo,  to  look 

at).     The  instrument  by  which  the  larynx  may  be  examined  in  the  living 

subject. 
LAR'YNX  (Gr.).     The  cartilaginous  tube  situated  at  the  top  of  the  windpipe, 

or  trachea  ;  the  organ  of  the  voice.  ^ 

LENS  (L.  )    Literally,  a  lentil  ;  a  piece  of  transparent  glass  or  other  substance 

so  shaped  as  either  to  converge  or  disperse  the  rays  of  light 
LIG'A-MENT  (L.  li'go,  to  bind).     A  strong,  fibrous  material  binding  bones  or 

other  solid  parts  together;  it  is  especially  necessary  to  give  strength  to 

joints. 
LIG'A-TURE.     A  thread  of  silk  or  other  material  used  in  tying  around  an 

artery. 
LYMPH  (L.  lym'pha,  spring-water).     The  colorless,  watery  fluid  conveyed  by 

the  lymphatic  vessels. 

LYM-PHAT'IC  VESSELS.     A  system  of  absorbent  vessels. 
MAL'LE-US  (L.).     Literally,  the  mallet  ;  one  of  tfce  small  bones  of  the  middle 

ear. 


318  GLOSSARY. 

MAE' ROW.  The  soft,  fatty  substance  contained  in  the  central  cavities  of  the 
bones  :  the  spinal  marrow,  however,  is  composed  of  nervous  tissue. 

MAS-TI-CA;TION  (L.  mas'tico,  to  chew).  The  act  of  cutting  and  grinding  the 
food  to  pieces  by  means  of  the  teeth. 

ME-DUL'LA  OB-LON-GA'TA.  The  "  oblong  marrow,"  or  nervous  cord,  which  is 
continuous  with  the  spinal  cord  within  the  skull. 

MEM-BRA' NA  TYM'PAN-I  (L.).  Literally,  the  membrane  of  the  drum  ;  a  deli- 
cate partition  separating  the  outer  from  the  middle  ear ;  it  is  sometimes  in- 
correctly called  the  drum  of  the  ear. 

MEM'BRANE.     A  thin  layer  of  tissue  serving  to  cover  some  part  of  the  body. 

MI'CRO-SCOPE  (Gr.  ftiKpoe,  mikros,  small,  and  CTKOTTCW,  skopeo,  to  look  at).  An 
optical  instrument  which  assists  in  the  examination  of  minute  objects. 

MO'LAR  (L.  mo' la,  a  mill).  The  name  applied  to  the  three  back  teeth  of  each 
side  of  the  jaw ;  the  grinders,  or  mill-like  teeth. 

MO'TOR  (L.  mc/veo,  mo* turn,  to  move).  Causing  motion  ;  the  name  of  those 
nerves  which  conduct  to  the  muscles  the  stimulus  which  causes  them  to 
contract 

Mu'cous  MEM'BRANE.  The  thin  layer  of  tissue  which  covers  those  internal 
cavities  or  passages  which  communicate  with  the  external  air. 

Mu'cus.  The  glairy  fluid  which  is  secreted  by  mucous  membranes,  and  which 
serves  to  keep  them  in  a  moist  condition. 

MY-O'PI-A  (Gr.  /zuw,  muo,  to  contract,  and  dty,  ops,  the  eye).  A  defect  of 
vision  dependent  upon  an  eyeball  that  is  too  long,  rendering  distant  objects 
indistinct ;  near  sight. 

NA'SAL  (L.  na'sus,  the  nose).  Pertaining  to  the  nose  ;  the  nasal  cavities 
contain  the  distribution  of  the  special  nerve  of  smelL 

NERVE  (Gr.  vevpov,  neuron,  a  cord  or  string).  A  glistening,  white  cord  of 
cylindrical  shape,  connecting  the  brain  or  spinal  cord  with  some  other  organ 
of  the  body. 

NERVE  CELL.  A  minute,  round  and  ashen-gray  cell  found  in  the  brain  and 
other  nervous  centres. 

NERVE  FI'BRE.  An  exceedingly  slender  thread  of  nervous  tissue  found  in  the 
various  nervous  organs,  but  especially  in  the  nerves  ;  it  is  of  a  white  color. 

NU-TRI'TIOX  (L.  nu'trio,  to  nourish).  The  processes  by  which  the  nourish- 
ment of  the  body  is  accomplished. 

(E-SOPH'A-GTTS  (Gr.).  Literally,  that  which  carries  food;  the  tube  leading 
from  the  throat  to  the  stomach ;  the  gullet 

O-LE-AG'I-NOUS  (L.  tfleum,  oil).  Of  the  nature  of  oil:  applied  to  an  impor- 
tant group  of  food  principles — the  fats. 

OL-FAO'TO-RY  (L.  olfa'cw,  to  smell).     Pertaining  to  the  sense  of  smell 

OPH-THAL'  MO-SCOPE  (Gr.  600afy/6f,  ophthalmos,  the  eye,  and  oKoneu,  sJcopeo, 
to  look  at).  An  instrument  devised  for  examining  the  interior  of  the  globe 
of  the  eye. 

OP'TIO  (Gr.  dpdo,  1tyofiai,futt  opsomai,  to  see).     Pertaining  to  the  sense  of  sight 


GLOSSARY.  319 

OR'BIT  (L.  or'bis,  the  socket).  The  bony  socket  or  cavity  in  which  the  eye- 
ball is  situated, 

OS'MOSE  (Gr.  wo/^f,  osmos,  a  thrusting  or  impulsion).  The  process  by  which 
liquids  are  impelled  through  a  moist  membrane. 

OS'SE-OUS  (L.  os,  a  bone).     Consisting  of,  or  resembling  bone. 

PAL' ATE  (L.  pala! turn,  (the  palate).  The  roof  of  the  mouth,  consisting  of  the 
hard  and  soft  palate. 

PAL' MAR.     Relating  to  the  palm  of  the  hand. 

PAN'CRE-AS  (Gr.  irav,  pan,  all,  and  «peaf,  kreas,  flesh).  A  long,  flat  gland 
situated  near  the  stomach;  in  the  lower  animals  the  analogous  organ  is 
called  the  sweet-bread. 

PA-PIL'L^J  (L.  papil'la).  The  minute  prominences  in  which  terminate  the 
ultimate  fibres  of  the  nerves  of  touch  and  taste. 

PA-RAL'Y-SIS.  A  disease  of  the  nervous  system  marked  by  the  loss  of  sensa- 
tion, or  voluntary  motion,  or  both  ;  palsy. 

PAR-A-PLE'GI-A  (Gr.  Trapa^aau,  paraplesso,  to  strike  amiss).  A  form  of  pa- 
ralysis affecting  the  lower  half  of  the  body. 

PA-TEL'LA  (L.  dim.  ofpat'ina,  a  pan).     The  knee-pan  ;  a  small  bone. 

PEL' vis  (L. ).    Literally  a  basin  ;  the  bony  cavity  at  the  lower  part  of  the  trunk. 

PEP'SIN  (Gr.  Kt-TrTu,pepto,  to  digest).    The  organic  principle  of  the  gastric  juice. 

PER-I-CAR'DI-UM  (Gr.  nepi,  peri,  and  /cap&a,  kardia,  the  heart).  A  porous 
membrane  enclosing  the  heart,  and  secreting  a  lubricating  fluid. 

PER-I-STAL'TIC  MOVE'MENTS  (Gr.  irepioT&hu,  peristello,  to  contract).  The 
slow,  wave-like  movements  of  the  stomach  and  intestines. 

PER-I-TO-NE'UM  (Gr.  KepiTetvu,  perileino,  to  stretch  around).  The  invest- 
ing membrane  of  the  stomach,  intestines,  and  other  abdominal  organs. 

PER-SPI-RA'TION  (L.  perspi'ro,  to  breathe  through).  The  sweat,  or  watery  ex- 
halation of  the  skin ;  when  visible,  it  is  called  sensible  perspiration,  when 
invisible,  it  is  called  insensible  perspiration. 

PE'TROUS  (Gr.  Trerpa,  petra,  a  rock).  The  name  of  the  hard  portion  of  the 
temporal  bone,  in  which  is  situated  the  drum  of  the  ear  and  labyrinth. 

PHAR'YNX  (Gr.  Qdpvy!;,  pharugx,  the  throat).  'The  cavity  between  the  back 
of  the  mouth  and  gullet 

PIIYS-I-OL'O-GY  (Gr.  <f>vaie,  phusis,  nature,  and  Xoyo?,  logos,  a  discourse).  The 
science  of  the  functions  of  living,  organized  beings. 

Pi' A  MA'TER  (L.).  Literally,  the  tender  mother  ;  the  innermost  of  the  three 
coverings  of  the  brain.  It  is  thin  and  delicate  ;  hence  the  name. 

PLEU'RA  (Gr.  nhevpd,  a  rib).  A  membrane  covering  the  lung  and  lining  the 
chest.  There  is  one  for  each  lung. 

PLEU'RI-SY.     An  inflammation  affecting  the  pleura. 

PNEU-MO-GAS'TRIC  (Gr.  Trvev/iuv,  pneumon,  the  lungs,  and  yaarffp,  gaster,  the 
stomach).  The  name  of  a  nerve  distributed  to  the  lungs  and  stomach;  it  is 
the  principal  nerve  of  respiration. 

PNEU-MO'NIA  (Gr. ).     An  inflammation  affecting  the  air-cells  of  the  lunga 


320  GLOSSABY. 

PRES-BY-O'PI-A  (Gr.  irpeofivc,  presbus,  old,  and  uip,  ops,  the  eye).     A  defect 

of  the  accommodation  of  the  eye,  caused  by  the  hardening  of  the  crystalline 

lens  ;  the  "  far-sight "  of  adults  and  aged  persons. 
PROC'ESS  (L.  proce'do,  proces'sus,  to  proceed,  to  go  forth).      Any  projection 

from  a  surface.     Also,  a  method  of  performance  ;  a  procedure. 
PTY'A-  LIN  (Gr.  TrrwaAov,  ptualon,  saliva).     The  peculiar  organic  ingredient  of 

the  saliva. 

PTJL'MO-NA-RY  (L.  pul'mo,  pv.lmo'nis,  the  lungs).   Pertaining  to  the  lungs. 
PULSE  (L.  pel'lo,  pul'sum,  to  beat).     The  striking  of  an  artery  against  the 

finger,  occasioned  by  the  contraction  of  the  heart,  commonly  felt  at  the  wrist. 
PU'PIL  (L.  pupil'la).     The  central,  round  opening  in  the  iris,  through  which 

light  passes  into  the  depths  of  the  eye. 
PY-LO'RUS  (L.  n-uAwpof,  puloros,  a  gate-keeper).     The  lower  opening  of  the 

stomach,  at  the  beginning  of  the  small  intestine. 
RE'FLEX  ACTION.     An  involuntary  action  of  the  nervous  system,  by  which  an 

external  impression  conducted  by  a  sensory  nerve  is  reflected,  or  converted 

into  a  motor  impulse. 

RES-PI-RA'TION  (L.  res'piro,  to  breathe  frequently).     The  function  of  breath- 
ing, comprising  two  acts:  inspiration,  or  breathing  in,  and  expiration,  or 

breathing  out. 
RET'I-NA  (L.  re'te,  a  net).   The  innermost  of  the  three  tunics  or  coats  of  the 

eyeball,  being  an  expansion  of  the  optic  nerve. 
SAC'CHA-RINE  (L.  sac'charum,  sugar).     Of  the  nature  of  sugar;  applied  to  the 

important  group  of  food  substances  which  embraces  the  different  varieties 

of  sugar,  starch,  and  gum. 
SA-LI'VA  (L.).     The  moisture  or  fluids  of  the  mouth,  secreted  by  the  salivary 

glands,  etc. 
SCLE-ROT'IC  (Gr.  OK%ijp6ct  skleros,  hard).     The  tough,  fibrous  outer  tunic  of 

the  eyeball 
SE-BA'CEOTJS  (L.  se'bum,  fat).     Resembling  fat  j  the  name  of  the  oily  secretion 

by  which  the  skin  is  kept  flexible  and  soft 
SE-CRE'TION  (L.  secer'no,  secre'tum,  to  separate).     The  process  of  separating 

from  the  blood  some  essential  important  fluid ;  which  fluid  is  also  called  a 

secretion. 

SEM-I-CIR'CU-LAR  CANALS.    A  portion  of  the  internal  ear. 
SEN-SA'TION.     The  perception  of  an  external  impression   by  the  nervous 

system ;  a  function  of  the  brain. 
SEN-SI-BIL'I-TY,  GENERAL.     The  power  possessed  by  nearly  all  parts  of  the 

human  body  of  recognizing  the  presence  of  foreign  objects  that  come  in  con- 
tact with  them. 
SE'RUM  (L. ).     The  watery  constituent  of  the  blood,  which  separates  from  the 

clot  during  the  process  of  coagulation. 
SKEL'E-TON  (Gr.).     The  bony  framework  of  an  animal,  the  different  parts  of 

which  are  maintained  in  their  proper  relative  positions. 


GLOSSARY.  321 

SPEC'TRO-SCOPE  (from  spectrum  and  CT/COTTCW,  scopeo,  to  examine  the  spectrum). 
An  instrument  employed  in  the  examination  of  the  spectrum  of  the  sun  or 
any  other  luminous  body. 

SPHYG' MO-GRAPH  (Gr.  a^uy^df,  sphugmos,  the  pulse,  and  ypdfa,  grapho,  to 
write).  An  ingenious  instrument  by  means  of  which  the  pulse  it  delineated 
upon  paper. 

STA'PES  (L.).  Literally,  a  stirrup ;  one  of  the  small  bones  of  the  tympanum, 
or  middle  ear,  resembling  somewhat  a  stirrup  in  shape. 

SYM-PA-THET'IC  SYSTEM  OF  NERVES.  A  double  chain  of  nervous  ganglia, 
connected  together  by  numerous  small  nerves,  situated  chiefly  in  front  of 
and  on  each  side  of  the  spinal  column. 

Sra-o'vi-A  (Gr.  avv,sun,  and  uovt  oon,  egg,  resembling  an  egg).  The  lubri- 
cating fluid  of  joints,  so  called  because  it  resembles  the  white  of  egg. 

SYS'TO-LE  (Gr.  auareMcj,  sustello,  to  contract).  The  contraction  of  the  heart, 
by  which  the  blood  is  expelled  from  that  organ. 

TAC-TILE  (L.  tatftus,  touch).     Relating  to  the  sense  of  touch. 

TEM'PO-RAL  (L.  tern! pus,  time,  and  tem'pora,  the  temples).  Pertaining  to  the 
temples ;  the  name  of  an  artery  ;  so  called,  because  the  hair  begins  to  turn 
white  with  age  in  that  portion  of  the  scalp. 

TEN'DON  (L.  ten1  do,  to  stretch).  The  white,  fibrous  cord  or  band  by  which 
a  muscle  is  attached  to  a  bone  j  a  sinew. 

TET'A-NUS  (Gr.  reh'w,  teino,  to  stretch).  A  disease  marked  by  persistent  con- 
tractions of  all  or  some  of  the  voluntary  muscles  ;  those  of  the  jaw  are  some* 
times  solely  affected  ;  the  disorder  is  then  termed  locked-jaw. 

THO'RAX  (Gr.  i?<jpa£,  thorax,  a  breast-plate).  The  upper  cavity  of  the  trunk 
of  the  body,  containing  the  lungs,  heart,  etc. ;  the  chest 

THY'ROID  (Gr.  tfypeof,  thureos,  a  shield).  The  largest  of  the  cartilages  of  the 
larynx  ;  its  angular  projection  in  the  front  of  the  neck  is  called  "Adam's 
apple." 

TRA'CHE-A  (Gr.  rpaxw,  trachus,  rough).  The  windpipe,  or  the  largest  of  the 
air-passages  ;  composed  in  part  of  cartilaginous  rings,  which  render  its  sur- 
face rough  and  uneven. 

TRANS-FU'SION  (L.  transfun'do,  to  pour  from  one  vessel  to  another).  The 
operation  of  injecting  blood  taken  from  one  person  into  the  veins  of 
another ;  other  fluids  than  blood  are  sometimes  used. 

TRICH-I'NA  SPI-RA'LIS  (L.).  A  minute  species  of  parasite  or  worm,  which  in- 
fests the  flesh  of  the  hog,  and  which  may  be  introduced  into  the  human 
system  by  eating  pork  not  thoroughly  cooked. 

TYM'PA-NUM  (Gr.  TvfiTravov,  tumpanon,  a  drum).  The  cavity  of  the  middle 
ear,  resembling  a  drum  in  being  closed  by  two  membranes,  and  in  having 
communication  with  the  atmosphere. 

U'RE-A  (Gr. ).     A  substance  secreted  from  the  blood  by  the  kidneys. 

U'vu-La  (L.  uva,  a  grape;,  The  small  pendulous  body  attached  to  the  back 
part  of  the  palate. 


322  GLOSSARY. 

VAS'CU-LAR  (L.  vasfculum,  a  little  vessel).  Pertaining  to,  or  containing  blood- 


VE'NOUS  (L.  v^na,  a  vein).     Pertaining  to,  or  contained  within  a  vein. 

VEN-TI-LA'TION.  The  introduction  of  fresh  air  into  a  room  or  building  in 
such  a  manner  as  to  keep  the  air  within  it  in  a  pure  condition. 

VEN-TRH/O-QUISM  (L.  ven'ter,  the  belly,  and  lo'quor,  to  speak).  A  niodifica* 
tion  of  natural  speech  by  which  the  voice  is  made  to  appear  to  come  from  a 
distance.  The  ancients  supposed  that  the  voice  was  formed  in  the  belly ; 
hence  the  name. 

V  SN'TRI-CLES  of  the  heart.  The  two  largest  cavities  of  the  heart,  situated  at 
its  apex  or  point. 

VER'TE-BRAL  COLUMN  (L.  ve^le-bra,  a  joint).  The  back-bone,  consisting  ot 
twenty-six  separate  bones,  called  vertebrae,  firmly  jointed  together;  also 
called  the  spinal  column  and  spine. 

VES'TI-BULE.  A  portion  of  the  internal  ear,  communicating  with  the  semi- 
circular canals  and  the  cochlea ;  so  called  from  its  fancied  resemblance  to 
the  vestibule  or  porch  of  a  house. 

VIL'LI  (L.  vil'lus,  the  nap  of  cloth).  Minute  thread-like  projections  found 
upon  the  internal  surface  of  the  small  intestine,  giving  it  a  velvety  appear- 
ance. 

YIT'RE-OUS  (L.  vi'trum,  glass).  Having  the  appearance  of  glass,  applied  to 
tlie  humor  occupying  the  largest  part  of  the  cavity  of  the  eyebalL 

VIV-I-SEC'TION  (L.  vi'vus,  alive,  and  se'co,  to  cut).  The  practice  of  operating 
upon  living  animals,  for  the  purpose  of  studying  some  physiological  process. 

VOCAL  CORDS.  Two  elastic  bands  or  ridges  situated  in  the  lar^s. ;  they  are 
the  essential  parts  of  the  organs  of  the  voice. 


IN  DEX. 


PAGE 

Absorbent  vessels. ..„ 121 

Absorption 119 

by  blood  vessels 119 

by  the  lacteals 120 

of  the  food 119 

Accommodation,  function  of 256 

Achilles,  tendon  of 35 

Adam's  apple 273 

Ague-cake 125 

Air,  atmospheric 161 

Changes  in,  in  respiration 162 

Composition  of 162 

Dust  in  the , 168 

Effects  of  impure 16 

Impurities  in 166 

Pro  vision  for  purifying 172 

Renovation  by  ventilation..    174 

Air-cells  of  the  lungs 156 

Air-passages 155 

Albinos 51 

Albumen 72 

of  the  blood 130 

Albuminoid  substances 71 

Varieties  of 72 

Properties  of 72 

Albuminose 117 

Alcohol,  as  a  fat-producer 151 

as  a  food 98 

a  poison  to  the  intellect 211 

Cold-promoting,  properties  of 93 

Effects  of,  on  digestion 125 

Effects  of,  on  the  brain 210 

Effects  of .  on  the  heart 150 

Effects  of,  on  the  kidneys 128 

Effects  of,  on  the  liver 126 

Effects  of,  on  the  mind 211 

for  thirst 99 

History  of 97 

Hostility  of,  to  life 101 

in  the  army 99 

impairs  the  will 211 

Kinds  of 98 

Properties  of 98 

Proper  use  of 101 

Trembling  due  to 210 

Alimentary  canal 105 

Animal  functions 184 

Animal  heat 175 

How  produced 175 

regulated  by  perspiration 178 

Animals,  relative  strength  of 85 

Apoplexy k....  203 

Aqueous  humor ...  252 

Arachnoid  membrane 183 

Arbor  vitae  ...  187 

Arterial  blood 135-165 

differs  from  venous 165 

Arteries 143 

Arrangement  of 143 

Carotid 144 

Pulsation  of ..  143 

Radial 144 


PAGE 

Arteries,  Temporal 144 

Arytenoid  cartilage 273 

Asphyxia 293 

Assimilation 104,148 

Audition 259 

Auditory  canal 261 

nerve 265 

Auricles  of  the  heart 137 


Back-bone 22 

Bathing 54 

Importance  of 54 

Time  and  manner  of. 67 

Baths 56 

Different  kinds  of 56 

Belladonna 249 

Use  of,  as  a  cosmetic 249 

Bile 118 

Secretion  of,  in  the  liver 118 

Accumulation  of,  in  the  gall-bladder.  119 

Uses  of 119 

Biliary  duct , 119 

Bladder 119 

Gall 124 

Bleeding,  how  stopped 149 

Blind-spot 250 

Blood 129 

Arterial 135 

Change  of  color 135 

Circulation  of 136-164 

Coagulation  of 132 

Composition  of 130 

corpuscles 130 

fluid 133 

Microscopic  appearance  of 130 

Respiratory  changes  in 164 

Uses  of  the 133 

Venous 135-165 

Blood-vessels 143,146 

Absorption  by ...  119, 120 

Injuries  to  the 149 

Body,  renovation  of  the 85 

Bor.es 15 

Form  and  composition  of 16 

Growth  of 24 

Microscopic  structure  of 17 

Repairof 24 

Structure  of. 17 

Uses  of 15 

Brain 183 

Anatomical  structure  of. 183 

Function  of  the 204,205 

Injuries  of  the 206 

Membranes  of  the 183 

Reflex  action  of  the 208 

Bread 92 

Bronchial  tubes 155 

Bronchitis...  158 


Canals,  Semicircular. . «, 265 

Capillary  blood-vessels 146 

Circulation  in  the *4& 


324 


INDEX. 


PAGE 

Carbonic  acid 162 

exhaled  from  the  lungs ,,.  16*J 

in  the  air 168 

Retention  of,  in  the  blood. 166 

Cartilage 21 

Arytenoid 273 

Cricoid 273 

Thyroid 273 

Caserne 73 

Cataract 252 

Cells,  Nerve 182,  192 

Ciliated 158 

Cerebellum 181 

Function  of  the 204 

Cerebro-spinal  nervous  system 185 

Cerebrum 184 

Function  of  the 204 

Cheese 73 

Chest,  Framework  of . 19 

Contents  of  the 19 

Chloral  hydrate 217 

Eflfectsof 217 

Chloroform,  Use  of 217 

Chocolate 97 

Chorea 202 

Choroidcoat  ofthe  eye 247 

Chyle 119 

Chyme .   119 

Cigarette  smoking 216 

Cilia 158 

Circulation 136 

in  the  frog's  foot 146,147 

of  the  blood 136 

Rapidity  of 148 

through  the  heart 139 

through  the  lungs 154 

Clothing 60 

Coagulation  of  milk 72 

ofthe  blood.  132 

Cochlea 265 

Coffee    '....    97 

Effectsof 97 

CoPar-bone 19 

Color-blindness 252 

Column,  Spinal 22 

Combustion,  Spontaneous 179 

Complexion  52 

Concha  of  the  ear 2*51 

Conjunctiva 243 

Contraction  of  heart .  138 

Contraction  of  muscles.  34 

Convulsions 207 

Cooking  89 

Cords,  Vocal .156,  274 

Cornea 247 

Corpuscles,  Blood 130 

Cosmetics. 63 

Country,  On  going  into  the 302 

Cranial  Ganglia 183 

Functions  of 204 

Cranial  nerves 188 

Cricoid  cartilage 273 

Crystalline  lens 252 

Uses  of 253 

Cuticle 48 

Function  of. 227 

Cutis...  .    48 


Decussation  of  motor  and  sensory  fibres 

of  spinal  cord 197 


•MM 

Dentition  of  infancy 106 

Diaphragm,    Movements    of   the,    in 

respi  ration. ..  „  - 159 

Diastole  of  the  heart 138 

Diet,  Mixed 85,  109 

Necessity  for  changing 87 

Necessity  of  a  regulated 7? 

The  best 78 

Digestion 104 

Circumstances  affecting 121 

Gastric 116 

Intestinal 118 

Nature  of 105 

Organs  of 105-118 

Disinfection 295 

Drainage 300-302 

Drain  diseases 300 

Drowning 293 

Duct,  Biflary 119 

Nasal 6 245 

Pancreatic 118 

Thoracic 121 

Dura  Mater 183 


Ear  .....................  .............  260 

External  ............................  260 

Internal  ...........................  2fi6 

Middle  ..............................  262 

Foreign  bodies  in  the  ..............  268 

Drum  of  the  ......  ,  .....  ...  .......    2QS 

Bones  of  the  ..............  .........  263 

Ear-sand  ..............................  265 

Ear-  stones....  .  ........................  265 

Ear-wax  ......................  .......  261 


Egg 
Co 


omposition  of  ....................    88 

Emulsion  of  fats,  in  digestion  .........  119 

Endocardium  ...............................  136 

Epiglottis  ............................  156 

Uses  of  .............................  156 

Eustachian  tube  .....................    263 

Exercise  ..............................    36 

Different  modes  of.....  ..............    39 

Effects  of  ...........................    37 

Importance  of  .....................    36 

Open-air  ............................    40 

Expiration,  Movements  of  ............  15d 

Extensor  Muscles  .........  .  ...........    32 

Eye  ...................................  242 

Eyeball  ...............................  24C 

Eyelashes  ............................  244 

Eyelids  ...............................  24b 


Fats,  Emulsion  of 7? 

Source  of,  in  food 73 

Fenestra  ovalis 266 

Fibres,  Muscular 34 

"  Nervous 183 

Fibrine  in  food = 73 

of  the  blood 130 

Fish,  as  food  91 

Flexor  muscles 82 

Food 65 

Animal ...    88 


Daily  quantity  of. 
Ingredients  of . . . . 


67_77 

Necessity  for 81 

Source  of 65 

Vegetable. 81 


JJNJJMJt, 


325 


PAGE 

G 

Gall-bladder 119 

Ganglia,  cranial,  Functions  of  the 204 

Gases,  Interchange  of,  in  the  lungs....  164 

Gastric  digestion 116 

Gastric  juice 114 

Action  of , 115 

Daily  quantity  of. 115 

General  sensibility 221 

Glands,  Perspiratory 53 

Salivary 110 

Sebaceous 52 

Glossary 304 

Glosso-pharyngeal  nerve 232 

Gullet.. 114 

Gum 77 

as  food 77 

Gustatory  nerve 232 

Gymnastics ...    41 

H 

Hair BO 

Uses  of 51 

Hasheesh 217 

Health  and  Home 300 

Hearing,  Sense  of. 258 

Protection  of 266 

Heart 186 

Cavities  of  the 137 

Circulation  through  the 139 

Frequency  of  action.... 139 

Movements  of  the...  137 

Valves  of  the 139 

Heat,  Animal 176 

Production  of 176 

Regulation  of 177,178 

Hemiplegia 198 

House,  Location  of 300 

Humor,  Aqueous 252 

Crystalline    252 

Vitreous 252 

Hunger 82 

Seat  of  the  sensation  of 82 

Hydra 182 

Hydrophobia 202 

Hygiene 13 

Hyperopia 254 


Incus.... 263 

Inorganic  substances  in  food 67 

Insalivation 110 

Insensible  perspiration 53 

inspiration 159 

Intestinal  juice 119 

Action  of 119 

Intestines 118 

Complete  digestion  in  the  small 118 

Villiof  the 120 

Iris 248 

Function  of... » 248,249 

Iron 71 

Proportion  in  ths  blood 71 

Proportion  in  the  food 71 

Joints .  19 

Vaiietiesof .... 20 

Juice,  gastric 114 

Intestinal 119 

Pancreatic 119 


PAGB 
•K 

Kidneys „  125 

Kerosene 298 


Labyrinth 265 

Lachrymal  canals 345 

gland 344 

Lacteals .  33 

Absorption  by 33 

Lactic  acid  in  gastric- juice 115 

Lactometer 88 

Large  intestines » us 

Laryngoscope 275 

Larynx 156,  273 

Production  of  the  voice  in  the 273 

Lens,  Crystalline 252 

Ligaments 19 

Light,  Theory  of 240,241 

Lime  in  the  bones f 16 

in  the  food 70 

Importance  of 70 

Liver 118 

Secretion  of  the 118 

Locked  jaw 202 

Long-sight 254 

Lungs 154 

Capacity  of ...  160 

Structure  of 155,  156 

Lymph 121 

Lymphatic  vessels 121 

M 

Magendie,  on  pain 224 

M  agnesia,  compounds  of,  in  food . .  0 . . .    71 

Malleus 263 

Marrow  of  the  bones 17 

Mastication 105 

Importance  of 112 

Meats 88 

The  cooking  and  preservation  of ....    89 

Membrane  of  the  tympanum 262 

Medulla  oblongata 187 

Function  of  the 203 

Microscope 281 

Simple 283 

Compound 284 

The  use  of  the 281 

Milk 87 

Composition  of. 87 

Specrac  gravity  of , 87,88 

Milk-teeth 106 

Morphine 216 

Mucous  membrane  of  air  passages. ...    157 

Muscles,  Function  of  the ....     31 

Flexion  and  extension  of 32 

Voluntary  and  involuntary 32 

Mu  scular  contraction «*-. 34 

fibres 81 

sense 231 

Myopia 254 


Nails 60 

Usesofthe ...  61 

Nasal  cavities 236 

duct 245 

Narcotics,  kinds  of 216 

Property  01 , , 216 

and  sleep 218 

and  digestion 218 


INDEX. 


PAGE 

Nerve,  Auditory 265 

Glossopharyngeal 232 

Gustatory 232 

Olfactory 236 

Optic 240 

Sympathetic 191 

Nerve  cells ...  182-191 

Nerve-fibres 182 

Nerves,  Cranial 188 

Spinal 1S9 

Functions  of  the 194 

Sensory,  functions  of  the 194 

Motor,  functions  of  the . . . , 194 

Sympathetic  system  of 190 

Nervous  system 182 

Cerebro-spinal 183 

Nervous  tissue,  Properties  of. 192 

Nicotine 214 

Nose 235 

Nutrition,  Processes  of 104 


(Esophagus  ...» 114 

Oil,  Sources  of,  in  food.... 73 

Old-sight 275 

Olfactory  nerve 236 

Optic  nerve 240 

Opiates,  Effects  of 216 

Opium,  and  its  effects 216 

Orbicular  bone 263 

Orbit  of  the  eye 242 

Organic  substances  as  food 71-77 

Organs  of  circulation  ..„ 136 

Digestion 104 

Respiration. 154 

Sight :. 242 

Voice 271 

Oxygen 162 

Amount  of,  consumed  in  respiration,  j.62 
Continually  supplied  by  the  atmo. 
sphere 173 


Pain,  Relations  of,  to  pleasure 224 

Sensation  of 222 

Lses  of. 223 

Pancreatic  juice 119 

Uses  of 120 

Pancreatin 119 

Paraplegia 196 

Parlor  gymnasium 43 

Passages,  Air 155 

Pelvis 19 

Pepsin .  115 

Pericardium 136 

Peristaltic  action  of  the  stomach 216 

Peritoneum 118 

Perspiration,  Daily  amount  of 53,  54 

Sensible  and  insensible 53 

Uses  of 54,178 

Perspiratory  glands 53 

Physical  strength 36 

Culture 40 

Physiology 11 

Animal • 11 

Comparative 11 

Human. II 

Vegetable „ 11 

Pia  mater... 183 

Vlasma  of  the  blood 130 

Pleura 155 

Pleurisy., 158 


PAOB 

Pneumo-gastric nerve. 0....  264 

Pneumonia 158 

Poisons  and  their  antidotes 290 

Potash  in  the  blood 71 

Potato..., 93 

Presbyopia. , 275 

Preservation  of  the  teeth 109 

Ptyalin 112 

Pulsation  of  the  heart 141 

of  the  arteries 143 

Pulse  143 

form  of  the 144 

writer 144 

Pylorus ,  114 


Radial  artery 144 

Red  corpuscles  of  the  blood 13ft 

Reflex  action  of  the  spinal  cord 198 

Requisites  for 200 

Uses  of 200 

Causing  convulsions 202 

Objects  of. 203 

of  the  brain 208 

Rennet 73 

Respiration 154 

Change  of  blood  in 154-164 

Frequency  of 159 

Movements  of 159 

Object  of 154 

Organs  of. 154 

Respiratory  labor 166 

Rest,  Necessity  for 44 

Retina 249 

Retinal  light 250 

Ribs,  Movements  of,  in  respiration....  159 


Saccharine  substances  75 

Saliva 110 

Importance  of. 113 

Secretion  of 110 

Salivary  glands 110 

Salt,  Common 68 

Importance  of 69 

Scalds ...  297 

Scars  from  burns 298 

Sclerotic  coat  of  the  eyeball 247 

Sebaceous  glands 52 

Secretion  of. 63 

Semicircular  canals.. „...> 265 

Sensation  of  pain 223 

Relations  of,  to  pleasure 224 

of  temperature 231 

of  weight 831 

Modification  of 221 

Production  of 220 

Variety  of 221 

Sense  of  hearing 258 

eight 240 

smell 235 

taste , 233 

touch 228 

Sense,  Muscular 231 

Thermal 230 

Senses,  Special 220 

Sensibility,  General 221 

Sewers,  Danger  from 801 

Short-sight 254 

Sick-room,  Care  of  the 298 

Sight,  Sense  of 840 

Organ  of 842 


INDEX. 


PAffl 

Sinews «,... ...    33 

Skeleton 19 

Skin,  Structure  of , 48 

Skull,  and  its  uses  19 

Sleep,  Necessity  for 44 

Amount  required 45 

Small  intestines 120 

Smell,  Sense  of. 235 

Nerve  of. 236 

CJses  of 237 

Smoking,  Effects  of 214 

Cigarette 216 

Soda  in  the  food 71 

Sound,  Production  of 258 

Special  senses  ..   220 

Spectroscope...   131 

Speech 271 

Relation  of,  tc  the  sense  of  hearing.  272 

Sphygmograph. , 144 

Spinal  column. 22 

Spinal  cord 188 

Decussation  of  the.... 198 

Direction  of  fibres  in....  .. 197 

Fnnctions  of  the 196 

Nerves  of 189 

Reflex  action  of 198 

Spleen 1-35 

Spontaneous  combustion 179 

Stapes u....  263 

Starch 76 

Irs  change  into  sugar 77 

Different  kinds 76 

Effect  of  boiling 76 

M  icroscopic  appearance 76 

Stimulating  substances 77 

Stimulation 212 

Stomach 113 

Digestion 116 

Movements  of u 115 

Secretion  of 115 

St.  Vitus' dance 202 

Sugar,  Varieties 75 

Sources  of. 75 

Sun-bath 60 

Sym  pathetic  system  of  nerves 190 

Synovia 21 

Systole  of  the  heart 138 

T. 

Taste,  Association  of 234 

Education  of. 235 

Organ  of 0 232 

Sense  of 233 

Tea,  Effect  of. 97 

Tears 244 

Teeth,  Temporary  set  of 106 

Permanent  set  of. 106 

Bicuspid 107 

Canine 106 

Incisor 106 

Molar 106 

Arrangement  of 107 

of  different  animals 108 

Preservation  of 109 

Temperature  of  the  body 179 

Extremes  of. 179 

Sensations  of 230 

Tendon  of  Achilles. 34 

Tendons 33 

Tetanus 202 

Thermae .    59 

Thermal  sense , 830 


PA«B 

Thirst .*.c 82 

Thoracic  duct 121 

Thorax 19 

Thyroid  cartilage 273 

Tissues,  Intimate  structure  of  the 282 

Human 288 

of  the  lower  animals  ., 289 

Tobacco 214 

as  a  poison 214 

Effects  on  the  young 215 

when  in  training 215 

Tongue 232 

Nerves  of 283 

Sensibility  of 233 

Touch,  Delicacy  of 229 

Organs  of 227 

Sense  of 223 

Trachea 155 

Transfusion 134 

Trap 300 

water 301 

Trichina  spiralis 91 

Trunk 19 

Tympanum  of  the  ear 262 

Membrane  of 262 


Urea.. 
Ureter. 


124 


Valves  of  the  heart 189 

of  the  veins 145 

Vapor,  Animal,  in  breath 162 

Vegetable  food « 91 

Vegetative  functions 181 

Veins,  Valves  of 145 

Venous  blood 165 

Changes  of,  in  respiration 162 

Ventilation 174 

by  window 175 

Ventricles  of  the  larynx. 275 

of  the  heart 137 

Ventriloquism 279 

Vertebrae 22 

Vestibule  of  the  internal  ear 265 

Villi  of  the  intestines 121 

Absorption  by 121 

Vitalknot 204 

Vitreous  humor 253 

Vocal  cords 156,274 

Observation  of,  with  laryngoscope. . .  275 

Voice 271 

Organ  of 273 

Production  of 276 

Varieties  of 277 

W  ' 

Waste-pipes 800 

Water.... 94 

Action  of,  on  lead 95 

Chemically  pure 94 

exhaled  with  the  breath 162 

from  springs  and  wells 94 

Proportion  of,  in  the  blood 67 

"          of,    in    the    tissues    and 

fluids  of  the  body 67 

Water-seal 801 

Walking,  as  a  means  of  exercise. 89 

Well,  care  of  the 801 

White  corpuscles  of  the  blood. 131 

Wisdom  teeth 1W 


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